Due to blunt pressure trauma you developed blood blister
You do not worry, it is just swelling containing blood which becomes clotted.
You do not squeez or rupture the area., otherwise it may become infected.
Keep the finger at rest. Be calm. Apply only thrombophob oint.
Take vitamin C
and K tablets.Cold
compresses may enhance improvement.
The lesion may clear in few weeks without any scar and complication.
This answer might be helpful to you.
Have early recovery.
Dr. Ilyas Patel MD