I agree with Dr Theng's answer to your question. Do not pick your insect bites no matter how itchy t especially if its on your face and you want to prevent scarring. Topical antibiotics (e.g. Fusidic Acid) help to prevent an infection, that might aggravate the bite and worsen scarring. Topical steroids (e.g. Hydrocortisone) will help reduce inflammation if there is an exaggerated immune response causing causes excessive inflammation.
To add on, keeping the area well hydrated with moisturisers during the recovery period will help reduce scarring. Remember to avoid sun exposure and to apply sunblock regularly to prevent darkening of the scar. Good nutrition and a diet full of vitamins and omega oils can improve scar healing as well.
Lastly, if the indentation does not resolve, you may consider injecting a collagen stimulator, PDRN (e.g. Rejuran Healer) into the scar, or using dermal fillers to fill up the indentation on your forehead.
Hope that helps!
Regards,
Dr Harvey Ho