I still have a golf ball-sized lump where my lipoma used to be 3 months after removal. Is this normal?

Thank you for sharing your question and I am sorry to hear of your lipoma complications.  It sounds as if you had a reaccumulation of fluid that may have become walled off by scar tissue. I would revisit your surgeon for an in-person evaluation and discussion of treatment options. 

Dear patient, If 20cc of blood was removed the first time it is possible that there is more blood or seroma that needs to be removed. I suggest that you go back to your surgeon and have the area examined. Sometimes there are fibrous bands or blood clots that locaulate the hematoma and don't allow all of it to come out he first time. Gentle massage and lymphatic drainage also help the healing process. I hope this was helpful. Dr David R.

That is almost certainly (hopefully temporary) inflammation/scarring from the hematoma, which may also still be present to a degree as it liquefies/resorbs (and is not a "recurrence" of the lipoma, assuming nothing was left behind . . . )  Should be safe to massage to speed along its resolution, but check with your surgeon, of course.