FIRST INDOOR GROW

It sure looks like a lack of phosphorus but it is most definitely caused by overwatering. I feel like I’m starting to sound like a broken record saying this but look at the whole plant. Leaves are all clawed/droopy and look swollen/puffy and stiff from being water logged while leaf stems are still pointing ☝️. She is eating herself because she has stopped photosynthesizing. I suggest you do all that you can to dry her out. Make temps warmer, increase ventilation is soooI important, reduce humidity, carefully poke air holes in medium and/or let plant sit outside of its pot, raise or dim lights to avoid added stress, don’t water again till completely dry and then resume watering and feeding at reduced rate and slowly ramp back up from there Cheers 🍻