Glad to hear your first shave went well. My jaw and chin area is one of the more difficult parts of the face for me to shave well, so don't feel too bad. With time and practice, it will get better.

If you've got a really heavy or course beard, then you might want to try a bigger razor, such as a 7/8. John Crowley has several 7/8s razors for sale on his site.

http://www.shavingshop.com/index.php?category=32

The rust spots are curious. It could be shaving cream residue. Just be sure to thoroughly clean, rinse and dry the razor before putting it away for the night. It may help to put a light coat of Camilla oil or Sterol on it to protect it.

Ed