Agreeing with the other, more experienced, posters that this looks like a rash. While you might not knowingly be allergic to something, allergies can develop over time due to exposure. You can never have had an allergy to something...until all of the sudden you do. I've developed a couple of allergies due to exposure. I had to change laundry detergents after 'suddenly' becoming so sensitive that I couldn't wear the clothing I'd washed. (Tide) I also developed an allergy to acrylic fibers due to repeated exposure. If you're still there and still diving, make a note of things you're coming into contact with. You might find that you're reacting to something you use frequently...or reacting to a change in products due to traveling.