You have to get your refraction checked and use your glasses regularly. Also take frequent breaks every 20 mins for 20 seconds from the screen as the headache may be because of continuous strain. The number usually should not increase at your age. However, you must still get an annual checkup done. If the headache persists, you should also get your intraocular pressure checked.

U have to use spectacles regularly.At this age no will not increase you can do eye exercises.to avoid eye strain. To get rid of glasses you can go for laser  refractive surgeries like LASIK .They are safe now a days

Hi ..mostly number becomes stable at this ages. There is no method to decrese or stop the number. You can do laser to get rid of number .