Agree with Jon86. You're fine. The pain will go away on its own. My failed hanging attempt was a bit more severe than yours. Couldn't swallow for a whole day because of the pain. Very visible rope burn around my neck. Some weird red splotches all around my face, I guess because of the constricted veins? All went away within three days. You have nothing to worry about. If you had passed out even for a little, that might mean brain damage. Although I've talked to a few people who had medically confirmed brain damage because of failed attempts but most of those people were fine, save for some memory issues.