Local injury while repeated plling and inserting the needle must have resulted in a counter puncture at the site, resulting in blood and Meth accumulation. This seems to be the cause along with venous inflammation and clots called thrombophlebitis. A local anti inflammatory ointment like Thrombophob can be used to ease the pain and inflammation. Also take some oral pain killers like Tylenol and some antibiotic after discussing with your doctor I would also like to advise you to use this incidence as an motivation for you to quit this habit and lead a healthy life. Thank you.