Welcome to the forum. You have severe symptoms of some bug bite
. It could have been a spider, bed lice or some other bug. You have sensitive skin and the infection is already in your blood since it is spreading everywhere ( palms. soles, feet, groin). You can apply cold compress in the areas affected so that you feel better. You can apply neosprin oitment locally( it is mild and effective). Treat your clothes with dettol or savlon
after use and let them dry in the sun. You can take anti-allergic tablet after consultation with an doctor in emergency room. ( do not take overdose of the medicine)
You have not mentioned but if you had been sexually active that night you need to rule out if your partner was not a carrier of the itchy disease from which you are suffering. It could be psoriasis
or STD which are all contageous infections. You should have a blood test
done ( VDRL, Australia antigen) to rule out contageous skin infection
and get treated in time.
Take good care of your hygiene, do not use the clothes of other people, limit the number of your sexual partners to enjoy a healthy lifestyle. It is better to consult a dermalologist if symptoms persists. Have a good day, take care.