Undissolved suture?

[D24]

Had excision around 6 weeks ago, surgeon told me to start massaging at 3 weeks post op. I started massaging but after about 4 days it started to become very tender around my areolas and I noticed a small amount of serous fluid (had been having a seroma on both sides aspirated regularly). I went to see my surgeon and he booked me in for an ultra sound, result was no remaining seroma and no gland left behind. Today while massaging I knocked a tiny scab and I noticed it was hanging on by something so I pulled it and a long piece of what looked like yellow string about 1 1/2 inches long came out and within minutes dried up and snapped. Is this normal?