Blood Blister 6 weeks after TKR

I had a TKR and all is well. I had staples removed at 10 days and wound looked great and then healed even though a few of the dissolvable stitches did make an appearance and my PT snipped them. But at about 6 weeks I developed a blood blister (pea size) over a suture. It bleed and the doctor squeezed the remainder of the fluid out, it healed then a couple of more popped up and they healed in a couple of days. I canceled the doc follow-up appt because all was well and then a couple of days another one has developed! Anyone else have this happen? (It is not infected but as a precaution the doc did put me on antibiotic for a week.)