Fiberglass is very smooth compared to asbestos, at a microscopic level. That’s what makes asbestos so bad - it gets in there and works its way further in, like a porcupine quill. Fiberglass is by no means healthy, but it’s a fair bit less harmful.

Asbestos can get to such a fine point that it can literally physically cleave DNA. Edit: I think I am wrong about that, please see my comment below

Yeah, and asbestos does that too and then gives you mega cancer in about 20 years.

Fiberglass probably won’t feel nice and might leave some permanent scars, but iirc, asbestos will do that and then some, but with particles so small that your body can never fully get rid of it