This ALLERGY thing is so common in dramas, mostly in those abt twins/ doppelgangers/ hidden identity, as it is uncommon in real life! SO MANY characters end up on a hospital bed because of some severe allergy, and SO MANY villains use it against our poor favourite characters, that it should have a BIG TAG of its own! Can't you just come with something new??
This romance drama - on a weird note - makes use of some well-employed tropes like amnesia, hidden identity, plastic surgery... And it's nicely executed all in all. But? At some point it becomes dragging - chinese dramas are always so long anyway - so i put it on hold for now.
Interesting idea and cast, you just gotta be in mood for it.