Hi, I painting the brick wall by mistake. How can I remove that?

If it is latex, use paint remover. The paint will still be tough to get out of the front face of the brick texture though. The only other way is sandblasting it off to get everything off. But you will compromise the front face texture doing it.

Almost impossible to totally remove paint from the pores of the brick without damaging the brick or killing yourself from the fumes of the stripper. Maybe another color?