Potential glass shard

So i cant post pictures , but i had punched a glass about a year ago , i have a big scar on my knuckle. About a month ago right next to it it began bruising and also swelling , it also stings and hurts sharply when i brush it agaisnt something , but not if i directly touch it. What is it? What should i do? I suspect its a glass shard that was somehow still in there.