The little worms under the blisters are what we layfishers refer to as sea lice. You would not believe the number of worms you can encounter on an Alaskan pink salmon. Its common for the pinks to have so many sea lice that the skin is gone in 15 to 20% of there body area and the sea lice are klinging to just about everything but the fins.
Flat worms are another parasite that is fairly common but usually in the gut and I don"t actually remember seeing any in the flesh.
Those little round worms that are in a spiral really gross me the worst, the most that I've ever seen were in Pacific true cod which when you get right down to it is a pretty gross animal in its own right!
I don't care to eat fish that is overcooked but I make dam sure if its raw its had the lime or lemon treatment like the Mexicans do. Don't really no if it kills all the parasites but I don't do raw all yhay often but re. parasites I'm pretty sure once is all you need to really screw up.