Suggest Treatment For Shoulder & Neck Pain

I got sunburnt pretty all over my shoulders and neck but my left shoulder is worse because about 3 or 4 years ago I was caught on fire and burnt up 11% of my upper body.. mostly 1st and 2nd degree but my shoulder spot was a 3rd degree dropped to a 2nd after further examination. But i was on a beach, used sunscreen and it obviously didn't work and now my left shoulder is blistering and i can't use it much. Is there anything I can do? I work outside, and i can't call off. The last 2 days have been horrible and wondering if any of you know of anything I can do to relieve the pain and maybe help it heal quicker. thanks.