Hello Welcome to health care magic. Scar after insect bite may be due to vigorous itching at bite site or pigmentation left after inflammatory response. It can be because of bed bugs,fleas or ticks. I would like to know where do you get bites on body ? What is your occupation? What you can do is apply hydrocortisone containing ointment locally over bitten area for 3 days to relieve the itch. Also take antihistaminics oral cetrizine once a day for 3 days. Most important thing is prevent further bites by using insecticidal formulations containing permethrin on your beds and clothings. Hope this information helps. Feel free to ask any more doubt.