Bugg with skin's overlayer

Today I have changed my account name and then my skin (with the web Skindex). All perfect except that the skin was completely black. Then I have realised that if I turn off the overlayer, i can see it. The problem is that i want to have my head's skin with the hat, and i can't. If I turn on the hat, i can't see my head's skin. I have tried it online and the other players told me that they were only seeing a black head.
What should i do?
Thanks for the help.