Welcome to the forum
Dry and itchy rash
under hairline, armpits, breasts, groin can be due to any food you consumed that did not suit you. You can take anti-allergy
tabs to get relief. It can also be due to infection, do not share your bed or your clothes with any one till you are not fine.
It can be due to use of some soap. lotion, cosmetic product, strong deodorants that could have caused it. Use mild medicated lotions or soaps. Since infection is also in the groin, get blood tests done to rule out STD
Get examined by a local doctor, it can be scabies
that is causing you restlessness
. If you are diagnozed with scabies, local application of scabiol lotion under hairline and in the body below the shoulder may be helpful ( before application do sensitivity test ). Do not apply on the face. One application is sufficient, take care.