Is it possible to get rid of creases on foams?

I bought a used pair of Foamposites and there's a pretty bad crease going almost all the length of the shoe on the instep. I was wondering if this is fixable because I might cry if it's not.

The first thing I tried was using a hair dryer on the creases and that didn't seem to do much. I did some googling and found out the foam used for these is polyurethane, and the best way to fix that is with steam but I haven't tried that yet because I'm afraid to do any damage to them. Has anyone else had this problem or know how to fix it? Any help would be nice because this is my absolute favorite pair of shoes that I've bought so far.