Answers:
Infra red radiation can be feel as boil. Too much warmness (infrared) radiation is harmfull. Try placing your paw surrounded by a fire and see what happen. This is an example to excessive infrared radiation. So if the boil go far into the tissue, it would acquire to the organs and would be a moment ago approaching frying the organs also. Mostly, it purely cause skin pull, to be precise if you're not watching yourself and sit in an IR sauna for hours, but that's not possible. IR is suppose to be the "least" destructive.