Small white bump on hand, help!?

I've had such issues lately, I've been diagnosed with a bacterial infection then was told to take cipro. The rash went away mostly but there was still a few dots so I went back and was given another weeks worth. I was then told the reason the rash was reoccurring was because I am allergic to staph so I was told to also put an ointment on the inside of my nose to help the rash. In addition I had an itchy spot on my arm and was told that I had a small patch of eczema (all in one visit, awful i know). Now I found this small white bump on my hand that doesn't seem to itch. It is slightly raised and literally came out of nowhere. Please help! I have prom in a week and am so upset with my skin right now! any help would be great, thank you!