I Am 51 Years Old And Have A Rash That

I am 51 years old and have a rash that will not heal on my upper back from shoulder to shoulder. Some I can feel are flesh colored, others have ulcerated center but small lesion <dime size. and scattered not in a pattern. It is not vesciular, not shingles. Does not hurt. Does not itch. and resolves leaves hyperpigmented area like scarred my skin. I wake up with more. bed bugs? I do have dogs that sleep with me but have for years. I thought hot tub follicultis but distribution wasnt really right, took cipro for 5 days did not change. Great derm doctor here but months to get in. But now been going on for months so should have tried. Angie Goins