Venusine, we all make mistakes. Bad ones. But as mature adults, we learn to get a grip and deal with issues as they arise. [I will apologize for writing that if you struggle with a mental health issue, but in which case, please consult with your therapist about how best to get through this.] In your chart is a little planet called Mars, along with your sun. They rule courage, and you may be called to develop them, just now.
In the meantime, let's assume you've stopped further damage from occurring, mopped up anything you could, and maybe talked to anyone who lives downstairs or checked the basement for leakage if you live on the ground floor. If you own an electric fan or even a hair drier, you can turn it on, aiming at spots you think might have been damaged.
Let's assume, unless you have evidence to the contrary, that the damage is minimal, or not as bad as you fear, once the affected areas have dried out. The long term danger is also getting mold in damp walls, so you want to avoid that, as some people's health is affected by mold.
I've been a landlady myself in the past (not now, thank goodness,) and it's pretty common for tenants to damage their living quarters. You won't be the first tenant to express concern to your landlord about a problem that you might have accidentally caused. Even if he gets annoyed, fundamentally he would rather have you tell him sooner rather than later. A problem caught quickly can be a lot cheaper to fix than one not discovered till much later.
Good luck with this Venusine. Please let us know how this turns out.