How long does it take to get oral cancer from chewing tobacco? worse if chew in off season?

It varies, but long.: Alcohol use and tobacco use are the main risk factors for oral cancer. Most are seen in patients over 50 years of age. Oral cavity lesions present as nonhealing ulcers that are sometimes painful. So, usually, it takes a long time for this cancer to develop. But some people have it sooner, especially if they have too much tobacco and/or alcohol. Talk to your doctor about stopping tobacco use.

Every chew releases: Carcinogens; the cancer may take years to appear after a single exposure. There are teenagers that have had disfiguring operations to save their lives. It is not safe at any dose.

Varies: Oral cancer has developed in teen agers from use of oral tobacco. Usually it takes many years. It is a very bad idea to use tobacco in any form. The sooner you quit the better.