They can obtain rehabilitation for you at an early stage so you do not suffer financially and concentrate on getting better without the stress. Once your injuries are stable, they can have your impairment assessed and recover for your damages for pain and suffering (which includes loss of permanent impairment— i.e. you might have a 20% impairment in your lower limb) loss of wages since the accident, and if applicable loss of wages in the future particularly if you cannot return to the same work performed prior to the accident.
A lawyer can also claim for future surgery, medical treatment, physiotherapy, medication, equipment needs, etc.
If you do not make a claim for your car accident you can be substantially out of pocket for the rest of your life.
I can assess the damages that would be applicable to your personal circumstances and the injuries suffered by you.
RELATED QUESTION: When should I contact an Attorney after a car accident? – Talking Law With White Jordin Lawyers