Suggest Treatment For The Bump On The Forearm

I had a small red bump on my forearm that looked like an infected hair. I now have a faint red line running about 1.5 inches down my arm. I have no pain, fever, lymph node swelling. It has probably been an hour since I first saw it. The ER sounds like an overreaction right now. What are the signs that I need to go to the ER?