ive gotten blistered shoulders and arms before (im irish too)
i just was all gimped out for 2 or 3 days
when they went away, they covered my upper back and upper arms in freckles, which have since somewhat faded (this was like 6 years ago)
you cant do much but stay out of the sun
(my blisters grew for 2 days after i got burned i had one on my right arm that was 1 1/2 in x 3 in, it was foul!)