Wonder what happened to Palmer after a while. That kid looked like the future of Chelsea and now when we look at him, we see that he is not doing that wonderful. So it's a questionable situation which causes a lot of trouble for him since he is not seen as great as he used to.
It is basically a dip in form, and it happens to most players, what matters is how strongly they can come back from a pretty bad form. In Cole Palmer's case, he is definitely a wonderful footballer with a great mentality, some of his bad form was due to a collective poor performance from the team, and remember that he has been carrying this team on his shoulders for sometime now. I am pretty certain he would be back to his best form next season, but it is up to his teammates to also step up, in order to achieve collective success.