1. That backlash, or rather the "cost" (the misfortune that she will face), could've been referring to the Lord himself. Whereas she gets to experience Lex, as a result of the magic, she also has to experience the normal Lord (not under magic), you know, give and take. In return for the "dream" lord (Lex), she also has to suffer (not that she does, anymore) through the normal cold lord.
2. The other possibility of the "cost" could be Lex turning yandere or something similar. Maybe the longer he remains as such, the "love" he showers her with will turn obsessive, or perhaps turn sour.
I'm thinking of 2 possibilities:
1. That backlash, or rather the "cost" (the misfortune that she will face), could've been referring to the Lord himself. Whereas she gets to experience Lex, as a result of the magic, she also has to experience the normal Lord (not under magic), you know, give and take. In return for the "dream" lord (Lex), she also has to suffer (not that she does, anymore) through the normal cold lord.
2. The other possibility of the "cost" could be Lex turning yandere or something similar. Maybe the longer he remains as such, the "love" he showers her with will turn obsessive, or perhaps turn sour.