That's how I found out I was allergic to sulfa based drugs. Was working out of town too, sick as shit and went to the doc. Get back to my room , happen to look at my hand and it's fucking yellow! Now when I have to fill out doctor forms and it asks what you are allergic to and what it does to you , I put: Sulfa - turns me a pretty shade of yellow.
One for the Picture gods!
BTW: This could be a repost but .......search function ?