met a girl dated a month we been sexually active then she went out of town for 2 weeks with family came back and we had sex in the hottub....

next night she was in a lot of pain saying it burned to pee and bring tears to her eyes I looked down there and was nothing no bumps nothing a little inflamed or irritated I guess... that was Thursday night... well we went to Vegas for the fri and sat. she was in pain fri just when she started to pee and like hurt walking sat was fine from drinking sunday was in tears again.... I checked again and on the left out side the vagina there was a small white ulcer? size of ingrown and maybe a little white discharge..... so I freak she went to the doc the next day and the doc ran her urine and said that there was some bacteria and blood in the urine and the ulcer could just be from that.... its just a bad uti the doc said!!!??? never swapped the ulcer or nothing said not to worry about it? said if it was green or yellow then yeah but its now??

What could this be