How do I deal with a public intoxication charge? I would like to have it expunged if not dropped completely.

I am a graduate student in the bay area and was out at the bars with friends. I had too many drinks. I remember being at a bar with my friends around 1:30am. The next thing I know, I'm being handcuffed by a police officer at around 5am. I have vague memories of running through the woods, away from someone. I found the nearest house and repeatedly tried to knock on the door, likely seeking help. The resident of the house called the police (perfectly understandable). When the officer arrived, I was covered in blood and had a gash on the top of my head. I also have bruises on my hip and legs as well as scrapes on my elbows and knees. I believe I was attacked. I was taken to a hospital, then jail where I stayed in a holding cell for 6 hours. I am charged for public intoxication and have a court date in about a month. Nothing like this has ever happened to me. What do I do? Is it possible to avoid this going on my permanent record?