Ask the Attorney: Is it too late to reopen a case?

Ask the Atty,
I got rear ended in an accident last year, the doctor told me that I would be fine with some treatment from a physical therapist and a lot of rest. It will be a full year in May
and I am still not able to do over 1/2 the things that I could before the accident and it seems to be getting worse!
If I go back to the doctor for a second opinion will it be covered by the other peoples insurance company, is it to late to reopen a case?

Ben J