The Phal abuse ends here.

[Rowangreen]

It's normal for the blooms to drop after all this time. I don't know if anyone else could comment on temperature: that would probably depend on the precise temperature! But I believe temperature drops can actually bring phals into bloom!

The marks: could the petals have been sitting against the window or something?

It might also be useful to post a picture or pictures of the plant, including leaves and roots/medium.

I wouldn't increase watering by the sound of it: phals need to dry out a bit between waterings.