I did have ED for a long time and I did not do snything for it. Long story but the thing is no matter what the reason if your erections stop it effects your penis health. ED causes size loss.
https://augustams.com/how-to-use-a-penis-pump-for-penis-exercise/ That is a great read and is for men who have RP but is the same for anyone with ED. Just wanted to add this as that exercise can not only prevent or slow down size loss it can also in some cases restore some size loss. You can also use this for sex but it is limited a bit in the number of time a week and the length of time the constriction ring is left in place. Talk to your doctor about this. A normal healthy man has a number of erections every day to provide for penis health. These even start before birth. If these stop that is when loss starts to happen. It can be a lot of work to do this every day. When I did this there were days I did not have time to do VED exercise. I would instead do some gentle stretching. I would place my index and middle finger below and thumb above my penis at the base of the head (glans) of my penis. Then gently pull straight out away from my body for a second or 2 then back to my body. Then repeat up. down, right and then left. I had good luck with VED therapy and stretching to help restore some of the size loss caused by my untreated ED.
As far as injections I have no personal experience with but I have read that some men had really good luck with them. They by trial and error found the amount of medication to inject for different lengths of time. 30 minutes or one hour or however long they wanted. Of course you have to be very careful to stay under 2 hours. Priapism is a serious and painful thing that can cause really bad damage. And can be caused with oral meds or injection. There are some videos online of men being treated in the ER for this and I would encourage any one who is using meds or injections to watch a few to understand fully the need to be careful. This is a really difficult thing for us men to go through but there is help. There are sites for men with ED to get a lot of information on treatments and support from men with the same issues.
If anyone would like more information please send me a Private message.