Various possibilities are there.It may be due to injury,boil,bunion,stress fracture,arthritis,gout and pseudogout, bursitis(an inflammation of the fluid filled sacs that protect the toe joints), arthritis-related enthesitis(Inflammation of the entheses due to arthritis. The enthuses is the site at which the tendon or ligament attaches to the bone),cellulitis(Inflammation of skin or subcutaneous tissues),lympadenitis(Lymphadenitis is swelling of lymph nodes due to inflammation) ,chilblains and trench feet(in extreme temperatures),lupus and systemic diseases like kidney and heart failure.
Exact diagnosis can only be made only after clinical examination.Although it appears like cellulitis or boil,but other conditions also cannot be ignored.A consultation of a dermatologist will be the best.
I hope it helps. Take care and pls do keep me posted on how you are doing or if you have any additional doubts. Kind regards.
I really shouldn't self diagnosis always seem to do it though. Hopefully will get in tomorrow and see he says.