Hello i recently finished my period a couple of days ago, and i still have quite a bad odour? it wasn't there before my period. is this normal? also - how can i prevent bv coming back? thank you

You may need to: check for a vaginal infection. If there are no other symptoms, such as vaginal itching, odor, etc. then you may be starting irregular spotting/ periods with your hormone cycle at your age. It could be very early on. As far as BV, there is not a lot you can do other than keep the area reasonably clean but not "too clean" i.e. not too much douching or chemicals. And mild soap is best.