If it's painful, then try gently cleaning the wound with cotton-balls soaked in a warm salt-water mixture.
Carefully wash the wound, and then carefully, but thoroughly dry it.
Leave it to air for a bit once dry, but do wrap it nicely with some form of gauze bandage.
But definitely visit your GP. They can have a look at it and tell you what may be wrong, and likely prescribe an antibiotic.
When you do this, also ask if they recommend washing the wound. They'll likely support the idea, provided you know what you're doing. It's often good to wash once or twice a day.
If you get antibiotics as a medicine, then make sure you complete your entire course of it.
Do not stop taking the medicine the moment you feel better or the infection appears to be gone.
Always complete a full course of antibiotics.
It's failure to do so that aids the development of antibiotic resistant bacteria.