cleansweap

You could have contracted an std. In the mean time, be sure and wash it (penis) good, especially under/around the foreskin. It won't hurt to apply some diaper rash cream from the baby isle in your super market. There are stronger creams and powders, but until you know which ones are safe, just use the diaper rash cream. If this is an std, you will need to see a doctor for treatment as soon as possible! Over the counter creams and powders won't due. If it's just a rash, use the diaper cream for rash, or corn starch, also on the baby isle/area.
Stay away from soaps with perfums, use something like ivory soap until you know what your problem is. Good luck!