Experience is what you gain after working year after year in the same way often without exposure to better ways of working and usually by following other people who have learned in the same on-the-job manner.
Expertise is what you attain when you also possess a superior level of real knowledge, skills and abilities.
For example, a pilot gains true expertise by applying what was learned at the training academy in multiple situations over a period of time and thereby also builds up top-notch experience.