This fabulous idea was given to me by Violet_purple-girl  so I decided to give it a try.

So basically Lucy was cursed by this one source and is stuck as a tiny child for three days. Id say she's five or six body wise but still has the say 17 year old mind set. No memories have changed, just her body. ~~~

LUCY

I was so small. Like, Im used to being the smallest and everything but know im literally like three feet tall. I know this will wear off but yeesh, do I hate this.

My legs are shorter so I have to run to just keep pace along side Lockwood or George. And it's not like im just shorter, I look like how I did when I was six; long hair, lighter eyes, squeaky voice! When it happened Lockwood was the first to run over and see a little me sitting dazed in big clothes. Yeah you heard me, my clothes didn't shrink. So he just kinda picked me up and wrapped me in my shirt. Now we were sitting on the floor in the living room. Just me and him. I was wrapped in my shirt still and a blanket.

"You're so small." He said amazed.
"What! When did that happen!" I said sarcastically.
"Heh, good to see your sarcastic side stayed."
He chuckled.
"I feel so weak." I looked down.
"Well you are like six again Luce. And hey, you never told me you had long hair."
"I know, I hate it. It gets in the way with everything. I chopped it off around the time I started working here."
"Its so weird. Your a child."
"It feels weird."
He started laughing really hard unexpectedly.
"What! What is it?" I asked wishing to get in on the joke.
"I suppose I can't kiss you for a while." I blushed at his remark. Yes it was true, me and him were dating. It happened about two weeks ago, we were sitting under the apple tree out back. The moon was full, thats when he told me his feelings. Before I had had any time to react he leaned down and kissed me. Now that I was six, I was sad that he couldn't kiss me.
"Har har, you think this is funny. IM SMALL!" I flapped my hands around.
"Your voice is so tiny and cute." He chuckled.
"So Im stuck like this for three days?"
"Thats what the inscription said." He leaned back against the couch. I looked down at my tiny hands knowing these three days where going to be the longest three days of my life.
"Im exhausted. You coming to bed?"
"Yeah." I stood up and let the blanket trail behind me as I walked beside Lockwood. He was going slow so I could keep up. Then we got to the stairs.
"Oh this is going to be fun- agh!" I screamed as Lockwood unexpectedly picked me up, holding me like a child.
"Hey, what are you doing?!" I clutched to him.
"It's going to take you ten years to go up. Thought I'd help." He smiled.
"Oh, thank you." He dropped me off on the landing outside my door.
"Good night Luce." He leaned down and kissed my head.
"Just letting to know when this is over Im never touching anymore sources." His chuckle carried up from the downstairs hallway.
"Wait! Lockwood!" I screamed.
"Yeah?" He yelled back up.
"Would this count as day one?"
A silence.
"To be honest Luce I don't know. I suppose only time will tell." And with the click of a closing door, I was alone.

Even getting the door open at this point was difficult. I hauled me tiny self to bed and fell asleep as my head hit the pillow.

When I woke in the morning I was disoriented at first, taking my time getting used to my smaller size. I plopped out of bed and slowly went down the stairs, blanket dragging behind me. When I reached the kitchen, only George was there.
"Where's Lockwood?" I asked trying to get into my seat, but ended but failing miserably. I was half on half off, bottom half swinging, face pressed into the back. My arms were stuck in my blanket under my chest, so for a while I hung there while George laughed.
"Help." I mumbled into the seat.
When his laughter died down he pick me up by the waist and plopped me down but sitting normal meant that my nose just reached the table.
"Um, George." He looked at me for a while then grabbed a huge book with no cover for me to sit on. It wasn't the best but it worked.
"Should I run to the store and buy a highchair?" He snickered.
"Im not a baby!" I screamed in a high pitch voice.
"Sure your not." He snickered again.
"Hey, George, be nice to Lucy. She's been through a lot." Lockwood said from the stairs. He bound down and took his place next to me.
"How ya' feeling Luce?" He said placing a kiss on top of my head.
"Short, small, young- which im not complaining about." He laughed.
"I really down know what your going to do on cloths Luce."
"Oh, im fine with the blanket really."
"Nonsense."
"Its only for a couple days Lockwood. I should be fine."
"You two are like a bickering old couple." George said from the stove.
"Can it George." I tried to sound menacing but with a child's voice, it just went south.
"Lucy's right, shut up George." Lockwood smiled at me.
"Wait, don't we have a case tonight?" I asked.
"Yes, seems we do. Don't worry Lucy. Me and George will handle it." He smiled him gigawatt smile and picked up a spare magazine.
"Darn, I was looking forward to this one. Two raw bones and a cold maiden. An odd bunch."
"Sure is. Don't you fret Luce. Me and George will tell you all about it when we get back. You'll be ok here alone right?" He looked genuinely worried.
"Hey, its me were talking about here."
"Exactly, thats why we asked."
"GEORGE!" Me and Lockwood bellowed. His voice over took mine. I slammed my forehead lightly on the table.
" I hate being small."
Lockwood chucked. He tilted my chin up and my eyes locked onto his. He placed a small kiss on my forehead and smiled.
"If theres one thing I will not do, is a kiss on the lips. I know your not actually six, but it would still make me feel weird."
"I get it. But im getting a really good one when im back." I warned. He let out a hearty laugh and smiled for like the hundredth time that morning.
"Oh yes you are. It's killing me right now not doing just that so watch out when your back."
~~~time skip brought to you by tiny Luce~~~

On the third night I feel into a horrible fever. My stomach kept making horrible sounds. Lockwood sat by me in the living room with a bucket by his side for good measures. He held my hand for two hours. Then he fell asleep. About twenty minutes after he fell asleep I felt this massive wave of exhaustion hit me like a truck and as soon as I closed my eyes, I was out.

When I woke up my head was hitting one side of the couch and my feet were touching another. I barred up on my taller legs faster then light itself and was so unsteady that in two seconds, I had a face full of carpet. Lockwood jump up as well from the noise I made and looked down at me. I flipped over to my back and stared at my hands, legs, everything. I was back to normal.
"Owwww, my legs fell asleep." I said as I waited for the prickles in my legs to go away. When they did I stood up slowly. Lockwood had yet to say anything, we just stared at each other. I was wearing his sweat shirt and my sweat pants. I jumped at him and hugged him as hard as I could. He responded quickly and put his arms around my waist and putting his head in the crook of my neck.
"Now I do believe," he said after a while. He pulled his head up and stared at me "that I owe you something." He grinned and before I could respond his lips were on mine. It wasn't soft and gentle. It was harsh and begging. He'd longed for this. Well he did say it was killing him. We only broke apart when we truly needed air. He stared at me with a sense of longing.
"My room. Now." I obliged.