Cheryl. Without seeing a picture it's hard to know what to suggest regarding the injury. Snakes suffer from mites and sometimes ticks, externally. Internally they can have worms. But in a healthy wild specimen a certain parasitic load is normal and the snake can deal with it.
Jennifer. You can find all the information you need to make a good start for Squishy by following this link.
http://www.thamnophis.com/caresheets...ake_Care_Sheet
Any specific questions, please feel free to ask.