Winston's elbow scarring is from his first ever fight with Garrote, broke his arm and lost much of the skin around his joint, which his power healed, but it never looked right again after.
Diss lost her flowy sideburns in her first fight with Garrote who tore them off of her
Shimi's head scar came from Garrote shooting him in the head with his projectile nail power, but luckily since the nail wasn't pointed it didn't penetrate, but cause a skull fracture and skinning which he hides by keeping his hair long, but you can still see it if he parts his hair)
The only scar Garrote has besides the ones from grafting other mutants limbs to himself is the one from Ren, who is the only person to almost successfully kill him. He was essentially dead before Q got help from a person who can regrow organs. After a couple days on ice in the bathtub being worked on around the clock he came out fine, but with a pretty size able scar.
Thought it would be fun to do a scar study from the cast with noticeable scars~ The only notable one I didn't do was Arturo, who has some burn scars from fighting Scab around his calves.