Question: Can I still wear this if im not a monk yet and havent been initiated, and what mantra do I say to offer to Lord Vishnu/Krishna? thank you

 Answer: 

There is no mantra needed for wearing tulsi mala and anyone can wear it.

After initioation usually one wears tulsi neckbeads with three strands, but others can wear tulsi neckbeads that go one time around.

Question: Is it resistant to water? So that i can wear it even while bathing

 Answer: It is advised to soak the mala in raw oil for at least a week before wearing to help protect it and provide water resistance.