My tips on facing painful past memories:
(Offered this in a Facebook group to someone who is doing Jordan Peterson's Past Self-Authoring program, where you write down the major events in your past that impacted your life)
1- Process one painful memory "dragon" at a time. If writing one bit was intense, give yourself at least one "sleep" before moving on to the next.
2 - Breathe. It sounds trivial, but when feeling old pain re-emerging, its instinctive to hold your breath in order to not feel. So feel and breathe slowly, deliberately, softening your belly, allowing your breath to descend down into your belly.
3 - Have Kleenex around, feel, and cry. The past hurts are lingering because they haven't been fully processed. The writing brings up the opportunity to process. Feel the emerging pain and welcome it, with full body awareness (emotional pain is body pain, so locate it in your body and stay aware of it). Apply together with 2 - (breathe!)
4- Stay present! The events happened in the past, but the lingering pain is happening now. Once tuned into the pain, avoid analyzing, giving meaning, interpretations or conducting dialogue mentally. Instead, stay in the here (body) and now.
5 - Complete the process! Connect with the pain, feel it, breathe through it, voice it (ouch, uncensored verbal expressions, any words or sounds that need to come out), move with it (make fists, frown, stomp or whatever comes naturally with your body) for as long as the pain is intensifying. When it reaches a peak, let go of it, open fists, soften eyes, tongue, jaw and belly, and take some time to relax your body. This step is an important one, as it completes the process of that particular experience, so it won't have to haunt you anymore.
6- Integration. Give yourself time to integrate. Integration is for emotional processing what digestion is for eating. You don't follow a meal with another meal. Sleep, go for a walk, dance, play, make love, do something pleasurable and creative, and don't talk about your experience for a while.
Success! You can do this, and it's going to be worthwhile your efforts!