What to do about wrong size helmet?

I bought my first helmet from Cyclegear, and while I thought the guy working there knew what he was doing, I'm starting to suspect I got a helmet one size too big. It's a Shoei RF-1200, clearance model so can't be returned, and according to the Shoei fitment chart I should definitely have one size smaller, as I found out after finally measuring my head. Doesn't feel "tight" like I'm hearing it should. Can I just get a thicker pad to make up for it, or do I need a completely new helmet? via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/e84xb4/what_to_do_about_wrong_size_helmet/?utm_source=ifttt