Hi,
As you are in the Phillipines I think you can get Neem shampoos?. If so this is very good for getting rid of lice.Wet the hair thoroughly,massage the shampoo in and leave for 4 minutes.Make sure the piggy does not get cold.Rinse off very thoroughly,towel dry or use a hairdryer.If the piggy lives outside it would be best to keep it indoors for at least a few hours after a bath.
What are the symptoms your piggy has?.Can you see the lice?.