Cisplatin kept Mike's blood pressure low during treatment. He had to stop taking his high blood pressure pills.

Peg Tube, it took a few days for his stomach to adapt to it. He had burning at first too. A little bit of stomach acid would leak out. Stopped after a couple days when the skin formed a tight vaccum around the tube.

He could still eat and drink normally when he got the Peg, so he had time to practice with it and work up to being able to have a full feeding.
Try smaller amounts to start or extend the time it takes to get to your stomach. If your's is a push the formula through a syringe PEG, clamp it off a couple times and wait a little while before pushing the rest through. Mike would take 30 minutes for each feeding, then time to flush before and after. He complained it was like a full time job to feed himself each day plus flush and hydrate.
No doubt, it was worth it, he made it through treatment and recovered very well.

Ginny