Rash That Crusts Over But Does Not Heal, Clear Fluid Discharge, Itchy, Burning

round rash looking spot, about 2 - 2 1/2 inches across, it has a hole in the center that that will crust over but never heals, like a scab , i scrape it off once a day and it has a clear fluid that comes out, and scabs back over. its slightly itchy, some what burn feeling like a scrape. i had something on my arm one night about 8 days ago while in the shower, i couldnt see it but i hadnt noticed before, i thought it was i tick, so i started fingernailing it and it come off, it wash down the drain before i could see it, when i got out of the shower and looked in the mirrow, thets when i noticed a hole, about the size of a pencile point, i didnt notice the completely round rash until a couple days after