I (24M) broke a promise with my girlfriend (25F) and I don?t know if I should tell her

I have been going out with my girlfriend for about 1.5 months and I started getting quite close to her and I like her a lot. I knew she has some chronic illnesses that interfered greatly with her life and she is really depressed about it.
One day after I admitted I checked her facebook page (which has some info about her illness and other stuff), she told me it?s ok and she expected as much, but asked me to not check her tiktok. I promised her not to and she said it?s not such a big deal, but it?s very depressing.
Well, about 2 weeks later, curiosity got better out of me and I looked up her tiktok and it is indeed very sad and painful (making me also realise how little I actually know her).
Anyway, now I feel extremely guilty about it and I don?t know what I should do. Part of me wants to keep it a secret and not tell her, but I would feel like I?m lying to her, and I really want to have an honest relationship with her. That?s why I want to tell her even if she loses all trust in me and would even want to break up, however I don?t want her to feel even more hurt than she already is. I know I messed up and I?m a jerk, but I?m wondering what you guys think I should do.
Tl;dr: I betrayed my girlfriend?s trust to not check her tiktok and now I?m at a loss of what to do
EDIT: I see a lot of posts criticising my girlfriend that she told me not to look at her TikTok. I want to specify that she did say after I promised her that it?s no big deal and and it?s all public anyway. I also now understand why she was reluctant about me seeing it since she is in her most vulnerable state there and I see why she would feel nervous for me to see it.


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