Hello guys! I’ve been having problems with my lemon plant. It was thriving in the summer (although I was overwatering it) . When I brought it indoors for the winter, it was doing alright for the first few months but then later it started to attract fungus gnats and most of its leaves fell off. I started watering it less and recently I used neem oil to kill some of the gnat larvae. I also moved it away from other plants and put it under a grow light a week ago. However, I started to notice some browning around the time I killed the gnats so I cut off the tip where it was browning. Unfortunately the browning did not stop and is even spreading. What do I do?