Paranoid. The most likely liquid falling from a tree would be water. Did it rain recently? The odds of a bat salivating in a tree on a sunny day is very very rare. Bats like dark places to rest during the day. Also, bats drooling? Also very rare. The saliva from a bat causing rabies comes from a bite, not drool. Also very rare to get rabies through the membranes of the eyes. So, please don't worry.