I Lost My Skin And Now I Am Only Steve

This may happen sometimes if you play offline, but it shouldn't be permanent (in my experience). I have never seen this bug, so I may be wrong, but it could be an issue with your computer connecting to the Mojang (computer) servers, but if this happens on a Minecraft (in-game) server, then there is likely an error with the file you chose. Next time you open the game, go to the "Skins" tab to see if you can find it there. If you have a backup or another copy of your skin's texture file, you can upload it through the launcher, which should fix it for you.

Duplicate of MC-101579