How did you cook that poor fish?!?!?
You say grilled but that doesn't jive with the picture.
Wait, you must have grilled it and then the skin pealed off didn't it? Yeah that's gotta be it. I don't like eating the skin either but I love salmon so don't fault you for discarding the skin though I do that before cooking.

Best way to cook it that I have found (and I cook a lot of salmon) is to do it on smoking hot (450-465F) cast iron griddle or pan in the grill or oven (grill works a little better as it gets hotter).

First get the fish out and let it sit out for an hour so its close to room temp then season it how you like.*

Get the oven/grill cranked as high as it goes then get cast iron heating up to 450-465F, once at temp spray it with a little avocado oil and put the deskinned and seasoned fish down on the pan/griddle and close the grill/oven. 6.5-7 minutes later its done to perfection (add 1-2 minutes in the oven), DO NOT open the oven/grill to check on it and for god's sake do not try and flip it. Just put it in and leave it for 6.5-7 minutes (7.5-9 if in the oven) and it'll be perfectly cooked. It works EVERY TIME without fail.

*I season the fish first with Chef Paul Prudhomme Magic Salmon seasoning on all sides, then on the top I slather it with stone ground mustard, and sprinkle a good bit of brown sugar over that. The sugar and mustard combine then melt into a glaze in the grill, runs down the sides fish and when it gets to the cast iron it caramelizes around the edges of the salmon portion.