Check Temp, airflow, Light, ph of runoff. Its too late to change her back, but you can atleast minor the damage. Do you water till runoff? its a must at this size or low roots will dry out.
Dont listen to stuff like: OuR EaRtH sO GoOd, No nEeD fOr rUnOfF
Dont know what it is, but the stem looks dry af to me