If the cable, the metal cable, that is conected to the nob for the hood release is indeed still conected, check to make sure when you pull on the knob that the cable is not stretched out, check to make sure there is not to much slack if there is you can use a pliers and pull on the cable, careful how hard you choose to pull on the cable as to not tear or snap it. If it is just jammed you should be able to view the hood latch through the grill, if you can reach the main latch with a screw driver you may be able to pry the latch open, otherwise through the grill you should see the bolts that hold the latch on to the crossmember, remove these bolts there shoulb be atleast 3 normally there is 4 to 6 bolts on this latch. After removing this the hood will be able to open you will need to know either remove the cable and inspect it to see if the cable is jammed or if it is the latch itself. If you were in an accident it is quite common for it to not lign up properly anymore and you will either have to bend the latch back, or get the body reapired or the latch replaced. Thanks for the question and please remember to select accept.
If this was helpful to you please select accept, and if you have any other questions please do reply. Thank you Eric