Tropicals & Tender Perennials: Question/advice, 1 by Anaid

Anaid wrote:
I was out admiring and tending to my plants and looking at my one and only Hoya I noticed at the very tip of one of the branches were a bunch of yellow looking things on the underside of the leaves. I cleaned it off and it turned into a gooey liquid. Im not sure if they were bugs all stuck together and I smushed them or what. Any one ever seen anything like that before or have any advice?

(pic of a leaf)