Verified answer

If it's nighttime, yes go to the ER, don't wait...Anxiety/Panic grows worse when all you're doing is thinking about your pain.

If it's during the Daytime, consult with your Doctor, explain to the nurse/counter-person that you're in need of a quick check-up.

Never wait.

It sounds like a staph infectection I'm no Dr though. If you feel like you can wait till the morning at least and find a clinic open on Saturday then do if you don't feel like you can wait then go now. But I would try soaking the infected area in a tub (or bubble bath) with Epson salt and applying neosporin or calamine lotion to it first. I had a severe staph infection on my finger to the point they were talking about amputating my finger but the Dr had me try that first and it was better in 3 days. But you still need to see a Dr as soon as you can not sure it warns for an er visit though.

Pain, redness, pus and swelling all sound like an infection. Urgent care is probably adequate as they can culture and give you antibiotics and you won't wait as long as you would in the ER. If no urgent care and it is spreading fast go to the ER, but expect to be the lowest priority on a weekend night.