Just make sure he has water to soak in and maybe something to rub against...a log or a hide that is rough. If his eyes are still cloudy he has a few more days to go and he will be fine...he just wants to be left alone now...garters are vunerable to prey when they are about to shed, so they hide and get defensive. His eyes should clear up and then a couple of days after that he will shed. When he sheds you hope for the shed to come off in all one piece. As soon as you get back, start misting his tank frequently. You may want to put an extra water dish in there now and cover his tank lid about 3/4 with a towel...this will help to increase humidity but leave air. Make sure the water dishes give him room to swim...but are easy for him to get out of.