Stopncii.org - look into it Ive never used it but it’s free and stops major platforms from allowing the images you have shared.
Second, screenshot everything from their tik tok profile to the chats youre jn off of tik tok, even any threats they’ve made or remarks that they’re spreading the photos to others and look into reporting it to your local law enforcement/cybercrime agencies. ChatGPT can help you find if you have this in your area if you get overwhelmed googling. It’s likely if you report based off the tik tok profile or secondary profile that these agencies can help block that persons ip or access to these platforms.
Third, block this person once you’ve got your screenshots of whatever you need.
Lastly, dont send pictures to people. We were taught at a young age the dangers of such actions and you messed up and that’s ok, I hope you don’t do it again. There is no concrete way to end this sort of thing, only ways to sort of mitigate it. And hope that no one you know at all sees it. If they do, time goes on and ppl dont care too much anymore these days.