dont cut your wrists..they are out in the open way too often and it is too easy to cut deep, bleed uncontrolably, get caught or have a hard time cleaning it up...good places are theighs, biscep, waists those all can be convered easily...
excuses could be you ran threw some bushes...fell skateboarding (if you skate) ..during school--got scratched on a desk..ect there are many..hopefully that helped