pregnancy rash and hives

Hi, I started having ringworm rash on my tummy at week 16, found the grandpa's pine tar soap and has been using it with cold water shower, the ringworm rash stops completely after, and now at week 21, the mini hives started on my tummy! I cant find any remedy for hives, went to the doctor n got some antihistamine and some steroid creams, but it doesnt work too after 5days. Any one able to help.