It all depends on what kind of lifestyle a person had before. If he was closed, spent little time on the Internet, then nothing special will happen. It's another matter if a person communicated a lot and is always in the spotlight. I think this person will lose a lot for himself in a month. It is highly unlikely that he will not be able to communicate normally after that.
Nothing. Sit in the net for a month and not go out? If a person is satisfied with everything himself, then he will not worry about this. It is too short a time frame for the development of social phobia or something similar.