3 1/2 weeks post op...question

I'm 3 1/2 week post op for PFD and Arachnoid cyst fenestration...I'm still having considerable pain..almost exclusively on the left side of my head, my eyes are still extremely sensitive. I've had very little incisional pain, it's a little tender to touch, but mostly numb still. My dr told me to call him if I got a "headache"..how do you know its a "headache" when you are recovering from brain surgery? Isn't it all a headache? LOL! I have put off calling him bc I think he will put me on steroids, which I do NOT want to do...(getting married in April..don't want to gain weight or be puffy..I know...vain, vain, vain). Any thoughts?