Seein a vet is indeed a must on this case. Base on the pictures, it seems that the sores came from an underlying issue (possible dysecdysis and dehydration and maybe something else). And Im sorry to say, but the underlying issue may have developed from your husbandry practices that needs to be corrected asap. If you cant take it to a vet, have someone who's willin to or at least have someone w/ better experience and knowledge on snakes look on your lil fella. Good luck