for the past three months around the time of period i get this lump on my finger that itches like crazy. its uncontrollable!! this morning i woke up and there was blister on top of the lump. i popped it and now it itches even more. the lump is red abd about the size of a dime, maybe a little bit smaller and its located on my pointer finger near my cuticle! if anyone has any insight on this it would be greatly appreciated!