I really, really slammed one of my fingers with a hammer quite a few years ago. (Yeah, don't hire me.) There was a huge blister under the nail. Went to the doctor. He lit a bunsen burner, straightened out a paper clip, heated one end of the paper clip in the flame, and then placed the hot clip on my nail. Sure relieved the pressure. That finger is actually still flatter than the others, but the nail is fine. (I didn't watch your video.)
