What Is The Treatment For A Bump On The Scalp?

i am a cosmetologist,i have a new girl client around 12, she has a brown kinda stickily bild up on the hair about a 1/2 inch from the scalp,her hair is long tight curly hair, i have tred everything to get it off i tried for about 5 hours . cas you tell me what it is and what to use to get it off and is this a medical problem or is it just gunk bild up from not cleaning her hair???