Are Thick Black Lines Near The Wound Post Tonsillectomy Normal?

I have recently had a tonsillectomy (6 days ago) and noticed some of the scabs falling off which i believe is normal. This morning though I have four thick black lines on one side (2 at the top of the wound, 2 at the bottom) which look like stitches. If I had to have stitches is this normal or should they be white?