What an interesting thread

The laws governing your rights are very specific to your particular state.
You need to know what your rights are before making a decision on any offer that is offered to you.
Your first goal is to feel better and know what, if anything you'll be dealing with... medically down the line...possible PT, followup care, loss of wages etc etc.
IF you already settled your pd (property damage) portion, what did you accept? 100% offered and secured? Or was it less than that? If less, they will likely reduce your P/S offer by the same %...

(ie you took 40%, you'll get 40% for this portion of your claim)
go slowly...perhaps consider a FREE consult with a local attorney to get a "feel" for your "case".
Not all attorneys are ambulance chasers and many actually know what they're doing

You would have nothing to lose by inquiring...
What is your states statute of limitations? Is it three years to file suit? No need to Rush a decision that will be final and binding....Know what to expect..be Informed to make the best decision for your situation.
Best of luck!