(obligatory Real Genius line.)
So, installing malicious software means your information can be accessed? SHOCKING.
That was my answer.
After popping a bunch of benadryl and being satisfied that my condition wasn't worsening, I elected to make a regular appointment with my GP instead of going to Emergency.
I decided to take a few photos of the skin rash before it went away, which allowed the doctor (three days later, when I was totally fine again) to quickly identify that it was indeed an allergic reaction, and based on where it appeared, the subsequent interview helped diagnose the cause. Worked great!