Removing hotfix glue from a dress?

[twinskaters]

My friend (a real person, not covering for my own self! ) is doing a crystal scatter on her daughter's dress, using Swarovski hotfix crystals. She accidentally placed one in a bad spot, then used the hot tool to re-melt the glue and get it off there. But it left a mark, of course. It's a satin-y nylon, not velvet, so she's pretty sure it's glue residue, not just crushed fabric. Any advice for how she should proceed in fixing it or at least mitigating the damage? It's a new dress and the spot is right over the belly button. 

[dak_rbb]

I use Goo Gone to fix mistakes and remove stray bits of E6000 glue.  It works great.  I would try it on a scrap or inconspicuous spot first of course.