Welcome To HealthcareMagic forum,
Its a sever sun burn reaction if you had a gone for swimming in the day time or early morning.This very common condition which we see after swimming .
You can use any mild steroid
cream in combination with antibiotic over the lesion and also use a sun-blocking cream when you go out in sun.For itching you can take one cetrizine
I hope this answers your query,if you have any further question ,you can write back to us.