When he kissed me on my cheek for a second time he kissed me on the side of my mouth (where my lips join). Did it mean anything different to a cheek kiss?

It would depend on the person. Different people attribute significantly different meanings to the same actions. However I think its likely that by moving the kiss closer to the mouth that it is intended to convey more intimacy that a simple kiss on the cheek. It may even denote an attempt to illicit attraction or desire for sex, but whether that succeeded depends on you.