Biting was my original self-injury method (starting at about age 6). I bit myself hard enough that it took more than a week to heal. The only time that I got locked up for SI stuff, I had done lots of things but not cutting. Biting and scratching myself were what did the visible damage.

One definition I have seen of self-injury is anything that you do as a way to cope with distressing emotions or mental states, that leaves a mark lasting for more than 15 minutes.

I'm not going to start giving you more ideas here, but there are many ways in which people self-injure. My T, who is familiar with SI, says that she is surprised at my variety of methods.