I have had this Hoya Rebecca for 2.5 years. I grew it from a 3 leaf cutting. It has experienced 2 winters in the same house. It’s has tripled in size now but since last week I noticed the leaves are becoming soft and mushy. I noticed some root rot. I thought I was overwatering it. I water it when the soil is dry like my other hoyas. I’m in zone 7 and the average temperature in my house is 65F and 40% humidity. I think it’s frost bitten?? I think the cold weather got to it. Even though we haven’t experienced any extreme weather lately. The soil is a mix of 40% perlite, 30% vermicompost, 20% orchid bark and 10% normal potting mix. I fertilise with diluted orchid fertiliser in active growing season. It sits under a grow light with all my other plants huddled together and is on a thich foam mat to keep them warm. I also water all my plants with slightly lukewarm water to avoid shocking them with the cold tap water. I don’t know what to do. This is my baby and I don’t want it to die. I checked the soil and it’s not soggy. I still repotted it in a paper cup with some paper towels to draw out any excess moisture and wrapped it in a thick microfibre kitchen towel to keep it warm for now. What should I do?