Hola
Just came across this post.
By now, trust you will have contacted a doc and all is well
Yes agree with one respondent that it appears to be an old insect bite reaction and subsequent post inflammatory hyperpigmentation.
It should be fairly straightforward to treat using a cream to begin with
If not, proceed to a spot peel.
Don't see it requiring lasers etc
Next Steps
Consult us Online with a current pic and details of any cream you may have tried in the last 10 days
Happy to Help sort it out.
Health Tips
Moisturizer like Aloe Vera can actually actually serve as a home remedy and may get rid of the mark.
Good Luck 🍀