Problems with my claim: Urgent advice needed

I had a car accident earlier this year where someone went into the back of me. I have been offered compensation and have received phycio however 8 months on I'm still no better and feel that I am going to be plagued with back and knee problems for the rest of my life. I have not accepted the offer yet because I want to take it further as I have not yet recovered however they have now asked to review my medical history and on there I have a history of back problems. Prior to the accident I had not suffered from back problems for a number of years so it is clear that the accident caused more problems than initially had. I worry that if they view my medical history they will see I have a history of back problems I will end up with no compensation at all. Should I accept the money offered to me or should I take it further and let them see my medical history? I want to pursue this and get the compensation I feel I truly deserve but don't want to end up with nothing.