Water Leak in Bathroom

I need some help with a leak we discovered this morning. After rennovating our bathroom (lifting toilet for new vinyl flooring) and putting in a new bathroom sink & vanity, our downstairs tenant heard a some dripping and running water. This evening he noticed a small water stain in his bedroom (directly underneath upstairs bathroom). When installing the sink, we did have a minor mishap and some water leaked on the floor. It was quickly swept up but I think a bit of water may have went through the hole on the floor that was cut out for the plastic water lines. Could the leak simply be a result of that? Any other potential causes? We have checked all of the connectors in the vanity and the bathroom floor is dry. What's the best course of action? If the dripping continues, should we cut a hole in the drywall downstairs and determine the source of the leak? I'm new to this and any advice would be appreciated.

Do you own this property¿ If not the owner of the property needs a plumber. If you are the owner, call a plumber and in the meantime have the downstairs tenant sleep on the couch.