@Sansan24 yes it looks like dry enough and for as long as it is allowed to dry in between waterings (not too dry) you can water your plumeria.
Look closely at the base of this, is that brown spot a rot? If it is, that might be a stem rot that could easily spread to the main trunk. Do a prick test, if it bleeds white your plumeria is good if it bleeds brown or looks like mushy that is not a good sign. I am hoping it is just a shadow that made it look brown.
