Dugtrio's Dig Trap

[Magic_Umbreon]

My Dugtrio uses Dig Trap and I flip heads. The following turn my opponent plays two warp point cards and I select Dugtrio to be switched back into the active position. Is Dugtrio immune from effects of attacks? Do I place 6 damage counters at the end of the turn?

 

[PokePop]

When Pokemon went to the bench due to Warp Point, the effect was removed. No damage counters are placed.