Brief Answer:
General Surgeon preferably.

Detailed Answer:
Hi.
Thanks for your query.
Noted the history, your age, symptoms and medication.
3/4 inch bump above left ankle that pain on pressure is indicative of a localized problem and most probably not related to the whole leg swelling where Furosemide has not helped.
The best diagnosis can be done by a General Surgeon assisted by investigations as needed.

Which side of the ankle the lump is - inside area, outside area, in front or back of leg and ankle?
Any history of trauma or varicose veins?
Please post clear and focused photos if possible and give feedback once you see a Surgeon and investigated.

I hope this answers your query and helps you.
With Regards.
Dr T Chandrakant.

---