A very interesting question, can science (the practical) cure regret (memory and the emotional).
You have read the Harry Potter novels but may not have picked up on the importance of the power of children and pre-teens in 'making magic' as means to protect themselves against physical pain and the things they fear the most. You are now moving from your magic-making in to a new and uncertain space and time with new consequences, but carrying a small bag of regret and shame along with your new, early-stage adult awareness to scientific wonders--from magic wands and spells to Stephen Hawking's works on bending space and time.
While time travel has been theorized to be possible, the Grandfather Paradox of time nullifies the altering of histories past, but does allow the possibility of a co-existing, parallel universe[2,3]. Of course Hollywood has given us wonderful pros and cons of such a possibility.[4,5]
And so my answer to you is this: You already have a time machine, it is your memory. You can not change your past but you can effectively co-exist with it by placing it in an alternative/parallel space (in your mind) as you move forward in the present. And the best way for you to time travel effectively is with the recorded memories of others who shared the same experience to positive results [6,7,8]