I Cut My Knuckle On The Top Of It On

I cut my knuckle on the top of it on a Roof shingle. it was a small cut but it went all the way down to I guess the knuckle itself. now that the cut is healed, there is a huge lump on my knuckle and it seems like it might be full of fluid however my knuckles only sore when I bump it real hard. and it is not read does not look like an infection. should I cut it open and see what happens