Suggest Treatment For Itching In The Anal Area

Hi, I ve been having a bad itch on my anus for about 2 weeks now. After a bowel movement it starts itching and it s very uncomfortable, also sometimes when I walk it starts itching. Usually after I m almost done wiping the paper has yellow and some light blood. I was able to to take a picture of my anal area and it had bright yellow substance on it and parts of my skin around the anus looked peeled off . I was on antibiotics about a month ago. And Also my tongue has a yellow coat on it (didn t have before the antibiotics) i don t know if it has to do anything with my anus. What s there I can do so I can get rid of this? I tried sitz bath, applied coconut oil, Prep H ointment and I use baby wipes after I go to the bathroom and also take Probiotics. They provide relief but the problem is still there. Thank you