My Minecraft skin doesn't work?

Basically in vanilla Minecraft my skin works but as soon as i switch to tekkit the it goes back to the steve skin. My skin face comes up in the bottom right corner when I open it btw.

The tekkit version is still set in minecraft 1.5.2
The Vanilla I'm playing is 1.7.2
I don't know the tekkit version but the launcher build is 395#

Please I'm begging you!

Did you do it at www.minecraft.net? That should work out.