Part2 boil forearm, after one day of antibiotics from er dr. arm has gotten bigger and is red from my hand to half way up my bicep. should i go er agn?

It may need drainage: Boils usually have to be drained before they heal. If the er doc didn't think your boil was ready to be drained yet, but now it's redder and more swollen, it may need to be opened now. Most boils can be drained in the office and don't necessarily need an er visit, but if you have fever, chills, or red streaks up your arm (or your doc can't see you today), i'd say go back to the er. See a doc asap.

Boil: When you went to er, did they determine the cause of the boil? Did they lance it? Did they do culture of the content of the boil (pus)? If the boil was not opened, it needs to be; then thoroughly irrigated and packed open. Change the dressings and re-examine in 24 hours. If the arm is getting worse, it should be rechecked by a physician. Adjust antibiotics according to culture reports.