Have faith in God. Believe that you receive when you pray.
Mark 11:24 "Therefore I say unto you, What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them."
I have only had two instantaneous healings in my walk with God.
I had a horrible migraine when we were going out to witness as a group. I asked the evangelist to pray over me and BOOM! It was gone.
I was playing the keyboard for a Pastor friend who was holding the church's very first service and I was the only musician. I had Tendonitis and the alter call was really long. My right arm felt like it was going to fall off. After the service I asked the Pastor to pray and BOOM! It was gone.
Many times I had to wait days, months and years for healings to come but I stood fast and never doubted. We can ask for God's favor for a quick healing but sometimes it takes a while.
About 25 years ago a woman I went to church with was in her 70’s. She wore glasses since she was a child but prayed for years that God would restore her eyesight. Well, one day He did and she had 20/20 in her 70s. Don't give up....no matter how long it takes.