I've always managed to find other spots, but I don't recommend that. If I don't find a satisfying spot, I have taken it too far by accident when trying to get the feeling/relief/blood/high/whatever from it. Maybe talk to someone about the change in relief from it? Might be time to find a new coping skill or start treating it as an addiction? Too much tolerance can be really dangerous with cutting (speaking as someone who dealt with the addiction piece of it and nearly died twice because my tolerance became too high. Though I have found that unlike drug or alcohol addiction, I can return to it with more control years later. Not recommended or suggested however).