I doubt it was diaper cream...but if you're concerned about certain quirks, a great book to read is "Quirky Kids" it talks about hand shaking in there as one of the quirks. :) If a teacher, child care provider or other parent has noticed something different, it's always worth investigating...it's probably nothing, but if it is something the sooner you get the child help the more likely you can resolve the issue and help them.
Here is a link to the book I have picked up a few times when my children do something out of the ordinary. It's a good reminder to see if the difference is a worrisome difference or just a little phase. :)
PS ~ I totally agree with the woman above my message...OT is worth looking into and she might just be working really hard on developing those ine motor skills...as for busy, by 3 year old and my 1 year old are both VERY BUSY and going all the time!!! They have more energy then us lazy adults ;) However, it's ALWAYS a good idea to not dismiss something, it's ALWAYS better to look into it. :)
PSS ~ I have heard of some people putting diaper cream on chapped lips...I really wouldn't worry about that at all...