Rashes On The Skin Of The Neck. Tried Hydrocortisone Cream. Any Suggestions?

I have developed a rash , so to speak. Roughly 3 weeks ago it started as a single red patch of skin on the side of my neck a little less than 1/4 across. Within a couple of days it had grown into an oval about 1/2 x 1 with the original area appearing whitish as if it had been a topical burn such as touching a hot oven rack. About that time I spotted another oval patch in my armpit which developed a whitish patch in the center, as well. At 3 weeks the original patch is now approximately 7/8 x 1.5 and is mostly just red. No other symptoms other than a slight itching when exposed to heat and sweat (working out). The second patch has enlarged a little, but not as much as the original. However, over the past 3 days I have had a succession of new small red patches (8) which are noticeably growing per the previous pattern. These new patches have no recognizable pattern, but are random in placement beginning at armpit level and now extending below the waistline. I have tried a hydrocortisone cream and plain raw aloe , but to no observable benefit.