What are my options to remove this scar tissue (knot) in eyebrow? (Photo)

First, scars (i.e. excessive fibrous tissues, varying concentrations, combinations and concentration of intralesional anti-inflammatory agents may prove useful for shrinking and flattening them. If, perhaps, the same agent, concentration and amount were used each time, this may explain the lack of response and simply increasing the concentration or combining with another anti-inflammatory may due the trick. If this is a dog-ear, then, following the injection of a local anesthetic, the use of light electrocautery will flatten the area. You would be wise to make sure that you are consulting a board certified cosmetic dermatologist. Best of luck.