Excessive self-consciousness: being overly aware of oneself and excessively concerned about others' attention or judgment; can also refer to a person who is like this.
彼は自意識過剰で、グループの前だと緊張して話せなくなる。
He is overly self-conscious and becomes too nervous to speak in front of a group.
初めてのデートで自意識過剰になってしまい、ぎこちない会話になった。
I became excessively self-conscious on my first date, and the conversation turned awkward.
SNSの普及で若者の自意識過剰が問題になることがある。
The spread of social media can sometimes lead to excessive self-consciousness among young people.