embedded splinter/infection in thumb

Apologies if this isn't posted in the appropriate forum. I work as a bartender and pricked my thumb around the joint when picking up a bottle skip a couple of days ago. Didn't think anything of it but the next day my thumb had swollen to double it's size and I don't have much movement in it. There may be a very small fragment of glass embedded in it or it might just be infected. I don't really have money to go to a doctor and I'm a bit worried I might have to take time off work if it doesn't sort itself out. Anyone know if I could get free medical treatment anywhere in Dublin?