Hello,

Thanks for writing to us.

It looks like you have synovitis of interphalangeal joint of middle finger. This is a condition where the membrane lining the joint gets angry and red, which leads to an accumulation of fluid. You should also try and recall if there is any history of hurting yourself in that peculiar spot. In that case, we could also be dealing with a fracture and fluid like feeling may be haematoma.
I would suggest that you see your general physician. We would need a formal examination and probably a X-ray of the hand to confirm these changes.
Hope I have answered your query. Let me know if you have any more concerns.

Wishing you good health

Regards.

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