Need help!!! TMI!!!!!

Okay so please excuse the picture I wore just spandex and pants today at work for 4 hours and I could feel them irratating me but didn't seem to care lol until I got home to change and seen bumps like a rash of some sort but now it's gotton worse just from early today... Any ideas on what this is??? My boyfriend had something Simalar not to long ago and I think his was a hear trash from wearing a harness at work cause it was in the same areas of the harness. But his is mostly gone. (Also, I didn't have a rash before I put the spandex on)