Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain it seems that the huge bump over the leg that is painful and itchy and has pus in it seems most probably be due to causes like hair
follicle infection, infected gland in the area etc..
It can also be due to infection over the skin leading to pus formation under the skin..
You should avoid scratching it as it can cause spread of infection and can lead to deepening of the infection to the inner layers of skin as well as become more painful..
I would suggest you to
consult a General Surgeon and get evaluated.
He can advise you a course of antibiotics, anti inflammatory painkiller and topical application of antibiotic,
steroid and numbing ointment..
Do warm compresses as it can ease in draining it off..
If it does not improve or start worsening then
Incision and Drainage can help in faster resolution..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.