What Causes Brown Vaginal Discharge?

hello there i would like to ask you about my problem that my girlfriend has. she had her period and when removing her tampon she said that there was some skin stuck to her tampon. we are both very worried and dont know what to exspect and to do. she has also been having pains in her reproducive area for 9months or so, and has also recently been getting a brown vaginal discharge. she is scared and does not know what to do. would realy appreciate your oppinon.