Talk to Ent Specialist on Tonsils

From past 4 days I've have a sore throat due to tonsils then I took amoxicillin and after 3 days my tonsils healed and pain reduced, but today "the 4th day" I've a swelling at the end of the lower left jaw, I am confused is it a swelled lymph node or it can be a tumor/lump, I can feel it by hand and when touching it a very mild pain can also be felt. It is moveable but neither soft nor firm, its like partially soft and partially firm, moreover there are also headaches which comes and goes.

Also I've heard that antibiotics course must be followed throughout the complete duration, as I've started self medicating myself therefore I don't know how long should the amoxicillin course be, yet it has been 4 days now, since I've started it.