I've had terrible stomach episodes in the past--stress-induced remnants of a bout of botulism (which was another blessing of healing on its own). There was one night I thought I was having another episode. But it turned out that I was having food poisoning. Again. And on an already weakened stomach, it was much more brutal than it might have been a few years before. I literally crawled from the back of the apartment into the kitchen where the Priesthood brothers were able to give me a blessing. Soon afterwards I was able to get some amount of sleep and had the strength to endure the rest of the night.
Another time I received some very sad family news. I was very young, and still new to such sorrow. And I was dealing with the recent break up of the man I had considered marrying. I was stressed with my first semester of college's school load (17 credits) and working a job. The family news sent me over an edge. I remember crying on the phone with my mother, and not being able to stop shaking. She told me to get off the phone immediately, call my brother and have him come give me a blessing. I did so. The shaking stopped. The tears were more in control. While there was a huge ache, the blessing brought a calming influence so that I could have a good night's rest and so that I could go about my school and work responsibilities.
I believe in the power of the Priesthood to help heal. And I know that a person's faith in being healed is paramount. But I also believe that Heavenly Father knows what is best, and that some ailments we don't heal from right away, if at all. My friend suffers from Locked-In Syndrome. She has received many blessings. A Priesthood holder does not say what they want to in a blessing. They must be in tune with the Spirit and say what the Lord wants said. They can petition the Lord for someone to be healed. But in the end, it is the Lord's will. My friend's blessings have often included pleas for her to get better. To be healed. But never have they been a command to the Lord to heal her (that should never happen). And they were never prompted by the Spirit to command her to be healed, because it isn't what they were impressed to say. She has not been healed. But she has been strengthened in so many ways. And she has touched hundreds of lives with her faith and patience.
Healing, like so many other things, is in the Lord's way and in His timing. And we have to have faith and trust that He does know best and that all things really will work together for our good.