Hi. I ve gone through your query and I can understand your anxiety. Most of the bug bites would heal by its own within a week and in few cases, it might turn out into blue or purple ring around it finally into an open sore or ulcer, crusty and turns dark. If the big bitten area becomes red and swollen,then it shows you have developed an infection. Monitor yourself for symptoms of infection like fever, chills, or swollen lymph nodes. If infection is confirmed then you can take - a course of penicillin group of drugs if you are not allergic to such drugs - Antihistamines & analgesics to relieve pain & itchiness - Hydrocortisone cream & menthol for soothing & to reduce swelling. - Ice packs can also be kept. Hope I have answered your query. Let me know if I can assist you further. Take care. Regards, Dr. Yogapriya V, General and family physician.