Recently had this bug bite on the top of my foot ankle. Not sure what kind of bug, but it itched for 4 to 5 days. My mistake was to scratch it which made it worse and turned it into a bright red dime size mark.
After reading some remarks on this site I did the following. Washed the area with warm soap and water, applied apple cider vinegar with paper towel let dry for 30 min. more ACV then applied Tea Tree Oil with Qtip and sprinkled some foot powder on top of the TT Oil. I started this 1 hour before bedtime. In the morning the itch was gone and the red mark turned dark reddish brown. I think this helped the healing process.