It's not as bad as it sounds, really! I have a hard time with my periods, they come and don't go away, or go away and don't come back. Let me think a minute here.
The last time I was on Provera I hadn't had a period for almost 2 years. It was pretty awful, heavy and painful. My sister who is a nurse says it feels like having your insides ripped out, but it didn't to me. However, the reason he was inducing my period was to put me on birth control. This is when I first found out I had PCOS. I never had Provera after that, though I needed it.
The last episode of bleeding without end I had to have a D&C, he wanted to do a hysterectomy but I wouldn't let him. I had a very heavy period EVERY DAY from October to the following March. No hormone he put me on would make it stop. My hemoglobin got down to 6, he said I could have a stroke or go into shock.

At that point, I was ready for him to do whatever he wanted to!
Now I am on a low-carb diet, and it is normal again. Comes when it's supposed to and leaves when it's supposed to! Thank goodness!
Now the scary part! You'll do fine, just keep some cramp reliever on hand and be sure to ask the doctor what to expect and when to call him if it turns out differently than he thinks it will. Don't be afraid to call him in the middle of the night, either! Hahahah, they just love that! Good luck to you.