shell indentations

by Autumn
(Glen Burnie, MD.)

I've had my young adult Russian Tort (Ollie) for just over a month. She is about 4 inches long and weighs .5 lbs. She's been to the vet, where she had a good check-up and no fecal parasites. She eats a diet of mixed greens, some carrots and once in a while some mushrooms. She gets a calcium supplement sprinkled on her food often with a mixture of crushed tortoise pellets. She also gets a weekly soaking for about 10-20 minutes.

She lives in a 55 gallon blue rubber maid bin with cypress mulch. Before I leave for work in the morning, I turn on her UVB light and leave it on 8-9 hours a day, then at night when going to bed, I turn on a night heat light. Her favorite thing to eat is romain lettuce hearts. She practically grabs them out of my hand. She does sleep a lot by burring down into the mulch. When she is awake, she is very active and recognizes me as her keeper, she knows my voice and face.
Yesterday I noticed that there are 2 "indentions" on the back her shell. It doesn't appear to be soft and it doesn't seem to bother her when they are touched. What exactly seems to be causing these "indentions"? Could it be something I am doing, or could it be that she is growing since she was been with me?

Please help. I love my little Ollie and want to take care of her the best I can.