One thing's for sure: Gluten exposure with celiac disease always leads to damage.
After gluten exposure, one thing is definite: some damage. So how long is the healing and repair process after a gluten exposure? Unfortunately, there is no black and white answer. Like so much of life, this is an “it depends” question. For people who are healthy, the healing process should not take more than a couple of weeks.
However, for those with celiac disease and other autoimmune diseases overall, completely healing the lining of the small intestine can take years. Everyone else falls somewhere in between. As promised, the timeline is vague and varies greatly from person to person.