Hi, Welcome to Health care magic forum.
It appears that you have an infection of the heal, may be due to the prick by sharp, or a blunt object, or may be its own.
I advise you to consult a surgeon for diagnosis and treatment. You may need to have an incision and drainage
of the heel.
Take more of green leafy vegetables, pulses, sprouts,and
protein rich foods to hasten the recovery.
Wishing for a quick and complete recovery. Thank you.