in the last 2 weeks I have developed a rash on my left arm inside the bend of my elbow.

I am 30 year olds and I am an esthetician, I also do spray tanning frequently, in the last 2 weeks I have developed a rash on my left arm inside the bend of my elbow. It started small at first and stayed for about a week, then magically went away. It didn't itch or burn it was just there. THen after using my at home tanning product and going to sleep that night I awoke to a red burning raised rash on the same arm, but now it was about 2by2 in size. Much redder and more pronounced. And now my right arm hasa small one starting in the bend of my elbow. What in the world is this, i am scared I hav never had skin problems before, I don't have insurace and really can't afford to go to the dr. if it's easily treated, thanks!