I think .....Some times bruises last for 1week to 2 ... which can be enough time.. when you are eaten by grief,stress ..... body loose insane amount of weight ....... and on top that I guess he is not eating properly ... only drinking ... that's why maybe ... I might be wrong ....
I think the part where loses all the weight is after this chapter as in the first chapter of season 2 was a time jump forward and now we’ve gone back to see how he gets to that state.
Time skip. This scene is just a flashback of why Mokyeon is on his depressed arc.
Ohhh. But why does he still look like he lost a weight
NOW THE WEIGHT LOSS DOESN'T MAKE SENSE. How long has it been since the incident that Mokyeon lose all of those fats and muscles?? His bruises and nanjo's looks so fresh.