Due to circumstances beyond my control (stupidity) I have in my possession a baseball cap that's probably a little bit too tight, giving me a headache.  Is there any true and tried way to mold it better to my head?  There's no way to return it and I guess I can give it to someone I know if I can't deal with it but of course I rather keep the darn thing. 

The darn thing fitted so well in the store...I don't know what happened...