My advice is to not hide, but let the light dispel the darkness,
Rather than hiding when one denies Jesus is the Christ, it is better to let scripture form the understanding and repeat scripture.

“Who is the liar, if it is not the one who denies that Jesus is the Christ? This is the antichrist…”

Again, my advice is believe and teach this instead of opposing it:

“Today in the town of David a Savior has been born to you; he is the Messiah, the Lord.”