Have no idea what was in your shampoo. Some are pretty natural and some are loaded with chemicals you might be allergic to. I have to also say, not sure why you'd need lubricant to do that, I know some like it that way but unless you're very rough with yourself it isn't a necessity. If it's that bad go see your doctor, if it doesn't look that bad and is just irritated, I assume it will go away. But nobody who isn't versed on rashes can tell you what it is. I'm not trying to make any comments on here other than I'm pretty old now so I've had a lot of sexual experience with others and with myself and I've never used lubricant and don't really know why it would be necessary to use unless again you're either doing it compulsively or doing it too hard. But to each his own.