1) That was a just punishment for Pharaoh, not evil. Anything just is an absolute good. It might be "evil" from Pharaoh's perspective, since it ended up causing his destruction, but not from the perspective of a just God.
2) The just punishment of Pharaoh was the vehicle of the Hebrews' liberation from Egypt - which would lead to another just punishment of Pharaoh when he was destroyed crossing the Red Sea.
God wasn't being evil towards Pharaoh in order to bring about a good. God was doling out Pharaoh's deserved punishment, in order to bring about good - and justice is an absolute good.
Could God have freed His people without hardening Pharaoh's heart? Sure, He could have given Pharaoh a change of heart -- but that wouldn't be just.
We're getting off-topic by a country mile here. If you want to continue, we should FReepmail.
At any rate, we have nothing to fear. God wins in the end.