One feature/purpose of namemc is to see everything that ever happened profile wise. You can easily delete skins on your profile though! If it's a name, Mojang can most likely change it for you. My name was changed to some weird thing and then Mojang was able to get it back in just a few days. To delete skins from your profile, go to your profile and click "(edit)" after it says "Known Skins (#)". Then, select a skin and click remove!
I am an above average male human being that plays block games.