Hi,
Thanks for posting your query at DoctorSpring.com

I have gone through the details and attached pics. It looks like contact irritant dermatitis that might occur due to insect or bug bite, exposure to any irritant( unclean water, chemicals, plants, soaps and detergent, any cream like a sunscreen too could act as an irritant and intensify rash).
Now to treat such cases, I usually prescribe a potent steroid cream like clobetasol or halobetasol cream mixed in calamine lotion twice in a day. Use a mild soap to clean the area like cetaphil cleanser .Do not apply any antibacterial solution like dettol or savlon. As sunscreen and sun exposure intensifies the rash, please avoid both of these till lesions resolve completely.
Hope this helped. Should there be any query,please write back.
Take care

Hello,
Unfortunately we only provide email consultations are not allowed legally to prescribe via emails, or phones.
I can only advise you what medicines need to be taken.
Sorry for the inconvenience.
Regards.