With both my iPhone and my iPad I experienced this problem.  I was able to continue using my custom skin on my iPad for several weeks because I didn't attempt to change my skin. Now that I have, I can't load any custom skin on my iPad.  The skin appears invisible, shown in the images below.  If I try to log in to a world while wearing the invisible skin it won't load and says my skin is corrupt.  If I log into the world in a marketplace skin, it's fine but if I switch skins while in the world, my character appears invisible.  It doesn't cast a shadow, my in game name tag does not appear to others, and any armor I wear and any thing I hold in my hand is also invisible.  
I create content on YouTube and I can't record again until I can use my skin again.  

The last image is of my character in game, third person.  But basically it looks like a spectator shot of the nether.