He was more than likely just hissing, they get kinda crabby while in shed. You can check his mouth for signs of an infection if you feel it's necessary. You do need to significantly increase your humidity, he will probably have a bad shed at this point, don't worry theres a sticky for that! But you should up it to about 70% for the duration of the shed. You should have a look at the caresheet if you haven't already.