I pulled the cuticle from my middle finger out when I was biting the skin there, then a few days later it started to swell and is still swollen and really sore. I keep it clean but do I really have to go to a doctor as I can't afford one or will it go away soon? Its been days now and is still swollen and very painfull if I bang it on anything.

Chances are that bacteria got in, and the swelling is your body sending blood cells there to fight infection. You can wait for your body to win or you can get antibiotics from a doctor or clinic. It's good to keep it clean. If it gets super red, doesn't heal in 7 - 10 days, or starts to spread, see a doctor.