Replying to Modifying my helmet to fit?

so I got my protec today and apparently their sizing is BS! No way that their medium is a legit medium because I have a relatively small head and the thing crushes my brain.

I bought it for only 15 bucks so its worth it to keep it so i just thinned out the padding in it by like half a centimeter, you think that was a bad idea, as far as safety, the padding in this thing is like an inch and a half to begin with and now it fits great and still snug with my beanie and goggles underneath