Can craze lines become worse or will they stay the same?

It may remain: The same or may worsen with worrying & stress. Massaging it with lotion or skin softener may prevent it from worsening.Take care!

Depends: Depends to your bite issues, if you clench and grind your teeth they may get worse.

Absolutely: Any fracture lines can coalesce, just like if you keep throwing rocks at your windshield, it will eventually crack/fracture connect and your car windshield will cave in. Think about the foods you eat and the challenges you give your teeth... Brittle foods, sticky, super crunchy, etc.

Possibly yes: Needs more evaluation of your occlusal condition and habits.

Worse: May stay same or more probably worsen with age. Avoid ice, hard candy, bones, summer fruit with pits, Opening nut shells with teeth.