If I could build a time machine and change what hurts me presently then I am destroying the very cause of building the machine in the first place and hence I conclude that the past can not be changed!
What if time machines are not meant for traveling into the past or the possible future but are the mediums for traveling into possible past timelines that were existing as the future at that time.
Maybe instead of going back and changing things I could just go and live in one such possible past timeline that doesn’t contain the cause of my present sorrow and hence I am not destroying my time machine either and doing time travel easily!
Don’t cry over your past however or how much it hurts.
You have the power to enter a different timeline everytime.
Travel into a better one.
It’s all in your mind! Open it. See through it and live through it! ☺