I can’t guarantee that you will keep your water resistance, however you can use a type of rubber sealant/cement. There is a type of rubber water resistant sealant that people use for repairing fish tanks that is water resistant up to a certain point. And since it is made of silicone you will still be able to press the button without any issues. You should be able to use a toothpick to apply it to the button. I’ll leave a link to a sealant that you may be able to use!
Hope this helps!
Link: https://www.amazon.com/Aqueon-Silicone-Sealant-10-ounce-Clear/dp/B0002ASD34