Change things slightly if you need to, but make sure that the "temp_pos"s are in order.
eg. temp_pos_x = skill20, temp_pos_y = skill21, and temp_pos_z = skill22

then use
vec_set(my.temp_pos_x, player_pos.x);
vec_sub(my.temp_pos_x, my.x);
vec_to_angle(my.pan, my.temp_pos_x);
and it should work out....