Hey there Blah! TendSkin works great if you use it regularly. It has a derivative of aspirin to help as an anti inflammatory. I would say after you wax or shave the knee - apply the tendskin (if you can tolerate the sting) - then keep applying each day. If the ingrowns are bad - twice a day.
Later, you may find the area around the pores starting to get a white ring... don't be alarmed - just stop using tendskin for a day or so and continue. This is just to use until the hair grows out of the pore to prevent infection... which should be relatively quick
If it isn't working for you, I'd recommend Bliss Spa Ingrown pads. I used Tend Skin consecutively for 3 weeks, but I did not see any improvements. But the Bliss pads work wonders for me even after 3 days of usage!