I wonder, to whose nightmares does the title refer? Will they be Cat's, for which a prescription of Clark's personal attention will be necessary? Or will they be Lois', because she will find out if Clark comforts Cat, even if all he really does is keep her company. At this point in time, she's not going to be very understanding. Nor does she have any security about the way he feels about her. She's as likely to jump to the wrong conclusion about Clark and Cat as she is to eat a gallon of chocolate chunk ice cream to ease her loneliness.
Or maybe Clark will have nightmares of Lois leaving him forever because she believes he's given up on her and taken up with Cat (who was, I maintain, sorely underused in the one season in which she appeared).
Very good start. Bringing Cat back and putting her in mortal jeopardy was an excellent way to fold in complications without forcing anything. Everything flowed so naturally, including having Clark's work pile up because he's "returning too many library books." This is going to be interesting.
So where's the next part?