Can Post-op Bleeding Occur from Use of Advil?

There are several classes of blood thinners that should be avoided before and immediately after surgery. These include:

Aspirin
Ibuprofen
NSAIDS
Coumadin, Plavix

These medications are not immediately metabolized in the body, so that they may last up to one month after you take them. It is advisable that you do not take blood thinners as listed above one month before surgery but this should be individualized by your physician himself. Our office in Santa Monica routinely gives a list of over 200 medications that cannot be taken before surgery. Check to see if your surgeon has a similar list.

From your description is sounds like there was either a small separation at the incision or you are having a small reaction to the sutures. Either way that area of your body is undergoing some inflammatory changes. This can cause a temporary increase in circulation and delicacy of the tissue.
When you removed the dressing some of the superficial blood vessels bled. Advil may be contributing to how long it takes those small vessels to stop but typically at 6 weeks Advil should not cause significant post-operative problems in normal patients with straight-forward post-op courses.
I hope this helps!