If you’re feeling triggered, see if there’s a practical action you can take to lessen your distress. Can you block that unsafe person from your Facebook, for example?
If not, reach out and tell someone safe how you’re feeling. Just express yourself! Human contact works wonders when you’re not feeling well emotionally.
Remember that you’re here in the present, and nothing from your past can hurt you. If you like, you may want to try some grounding exercises to reinforce that idea.