I an understand your concerns,I think the knot is the healing connective tissue
inside and the pain indicates that the area is still a bit inflamed. In such a case it's better to start.
400mg three times a day after your main meals for just couple of days.
2: Fusiderm-H ointment would be a better option if you can have it OTC to spread up the healing and reducing the inflammation.
If the treatment responds in 3-5 days then its a good sign but if not then you have to see your doctor in order to do an x-ray of the leg to rule out anything serious like fracture
I hope the treatment will relieve your problem.
Thanks very much and all the best.