I have never heard of using sunscreen but think it is worth trying. It is too bad the circumstances that you heard about it. It sounds like he really got a good bite in.

I am sorry that your pet guanaco has gotten to be so big and strong. I am glad that you were not hurt any more than you were. I do hope you can find a home for him soon as he has now won a battle. Be careful around him. Take care.

BB