I Had A Schwannoma Removed From My Sciatic Notch 3

I had a schwannoma removed from my sciatic notch 3 weeks ago. I am experiencing pain at the surgical site running down the back of my leg to my foot. I am still taking Dilaudud 2 mg five times a day with a Tylenol.
My PCP has prescribed neurontin 300mg 2 times a day and 600mg at night. I've been taking it for two weeks.
My question is how long does nerve pain usually last?
I also,massage the sore areas and use a heating pad a few times a day.