15 month old with rash on calves

My 15 month old has had this bumpy rash on the back of both her calves for about a month now, since she began walking. She has been completely normal, it doesn’t seem to bother her, and it hasn’t gotten any worse since I first noticed it. I figured it was just something to do with dry skin so we’ve been moisturizing more. She has a checkup Monday but has anyone experienced this with your child and have any idea what it could be?