On honeymoon in mexico. Blood in urine. Should I pick up something at pharma?

Honeymoon cystitis. Sorry you have this classic problem. We healthtap consultants can make suggestions , but can not prescribe or treat. Antibiotics can be purchased over the counter in mexico. Thus suggest you visit a reputable pharmacy and discuss problem with pharmacist who may prescribe a good brand name antibiotic for you. He may suggest macrodantin, Bactrim or cipro, (ciprofloxacin) all of which could be appropriate. Good luck.
Honeymoon cystitis. The most common cause is- a urinary tract infection or called " honeymoon cystitis" it would need to be treated with antibiotic. The term "honeymoon cystitis" has been applied to this phenomenon of frequent utis during early marriage. If bleeding continues-need to rule out possibility of trauma i.e. Laceration of vaginal canal/cervix. See a doctor and they will prescribe you with antibiotic.