Hi Courtney, and welcome
your plant looks good. I love all the flowers, is that all one plant? The flowers on my Phals usually wilt before they fall off, so I don't think that is a problem. I'm not sure why the buds blasted, could be a number of things. You mentioned the hot spell, that would be my first choice, but like you said both over watering , and under watering could also cause that. if you search the forum for 'skewer method for watering' that might help you determine when to water. Good luck