I agree he looks super skinny there, but maybe because we never really see him in a sweater before? I don't know how recent this is, they might have just taken the tape off his chin since he is filming a CM, or this was done before the season and the wine sweater is just a costume to fit with the theme.
For those of you who probably doesn't know, in Japanese culture Valentine's day is the day that female gives male chocolates, while White Day, which is March 14th, is the day the male retursn the favor. Usually it's of course symbolic of affection but there is the well-known "friendship chocolate" which the girl gives chocolate to everyone (in the class etc.)
I believe those three girls are all spokesperson for the same brand of chocolate, and they wrote messages of support. (as well as in the video) Hanyu-san was thanking them for their hard work writing with chocolate and he said that their support has been received and he will do his best to have performances that give people smiles in the future too.
He was reminiscing about the time when he was in the skating club, where most students were girls so he would get their "friendship chocolates". So therefore he would have to think "oh now I have to give chocolates back to all these girls on March 14th!" which is a big task.
Very rough translation but I hope it helps somewhat.