Hi! I am super new at caring for plants. Doing okay so far, but my Hoya Heart has a dark brown/black spot in the middle of it that seems to be growing. It’s not soft (yet) but it looks bad for the little guy. The plant arrived a little damper than I think it should have been, bur I’ve gotten it to dry out quite a bit and even the deeper soil in the planter is fairly dry at this point. Other than the dark spot, the rest of the plant looks to be doing well. Does anyone know what’s going on and how I can save it?? Thanks!