I Had a Brow Lift Using Screws and Two Years After Surgery my Head Started to Swell in That Region?

Since your surgeon tried drilling the screws in even further they were likely made out of titanium.  Titanium is very well tolerated by the body if it is rigidly fixed (i.e. not loose).  If titanium is loose it can become infected and the treatment is to remove the screws.  If the screws were absorbable there can be some foreign body reaction as the screw degrades and this can also be scraped out and removed.  Please follow up with your surgeon to have this checked out. 

It is not rare that the body can react to any indwelling foreign material. If there are persistent inflammatory reactions that is an indication that the resolution of the problem is going to be the complete removal of the material. It would be helpful to know what type of screws were used for your browlift surgery.