Hi!
I've had this plumeria plant for about two years and never paid much attention to it until now. It's always bloomed maybe once or twice a year. I'm not sure if I over watered it. But I came home from work one day and it was slumped over like it fainted but everything else looked intact. I thought it was because I live in Florida and it needed water, so I gave it more water. Now, I'm realizing maybe the slump is from over watering? I'm also noticing these white blister looking things where the plumeria flower stems from. See pics. I have a trellis to hold it up so it doesn't snap. What's causing this?!

I'm guessing lack of sun and over watering.

My first thought was lack of sufficient sun and a bit too much water too. Frangipani (Plumeria rubra) do best in full sun locations.

I will try this!

give it more access to sun, as much direct sun it can get.

For it to slump so suddenly means it is a watering, not a light problem. If it was underwatered, it should have perked up after watering. If it was overwatered for an extended period of time, then the roots may be badly damaged and unable to absorb water even when it is available in the soil.

You might consider pruning back the tall stem.

The sap droplets are not a cause for concern.

I see no need to prune that plant. Just stake it for now, to help the plant as it slowly regains its balance once you finally improve its lighting access. As much full sun as possible.

Plumerias, once fully awake and established, is one of my favorites here when we are in these heat wave conditions, one of the few plants I have that truly enjoys direct sun and our triple digit temps, but have to water daily now that summer temps is here.

Your area definitely has better humidity levels too, so your plant should eventually adjust once you improve the lighting and be more consistent with watering.

Pruning is an option, not a necessity. It is a way to avoid stakes and other artificial props. Personal choice.