Shoulder blade rash

A month ago I surfed for 7 hours straight one day then about 4-5 hours the next day and developed 2 nasty rash/bloody scabs/now slight scars on the back of my shoulder due to the seam of the wetsuit sticking out a bit. Now it seems I get a rash more easily.

What can I do? Put some kind of flexible waterproof tape over the wetsuit seam (or on my back?), put some type of glue over the seam so that its smooth? I tried putting that newskin thing but it didnt seem to help at all. Dont want to pay for a rash guard and if i can remember i had one that caused a rash due to the seam also.