That is where he was attached to the yolk while he was in the egg. It looks like a little spot of dried blood. It will probably come off next time you soak him. You DO soak him, right?
Yes i do thank you also i have had him since August of 2014 and ge is still about the same size i feed him greens dust it with calcium some time i give him wet pellet food he has uvb light heat lamp basking area of 90 or up take him out when there is lots of sun he is a hatching