Please reply🙏🏽. How do i sleep after Tympanoplasty with cortical mastoidectomy surgery?

I went through Tympanoplasty with cortical mastoidectomy on my left ear 9 days ago and since then i have been sleeping on my back. Now i am feeling pain, bored and stuck when I lay down on my back. Can i sleep on my unoperated ear? I fear sleeping on an unoperated ear may cause gelfoam or whatever they have put between my eardrum and middle may fall in the middle ear.