Yes, a cavity can stay quiet and then become obvious fast
A small cavity does not always hurt right away. As decay moves deeper or weakens more of the tooth, patients may suddenly notice pain with sweets, cold air, pressure, or chewing.
That change can feel abrupt even though the process was building quietly over time.
Why the pain does not always mean the same thing
Sudden tooth pain can come from a cavity, but it can also come from a cracked filling, a deeper infection, or exposed dentin from wear or recession. That is why the symptom matters, but the cause still has to be confirmed.
Pain that lingers, wakes you up, or worsens with heat may suggest the issue is more advanced than a simple early cavity.
What to do next
If the pain is new, do not wait for it to either disappear or become severe before you call. An earlier evaluation can keep a smaller problem from turning into a much bigger one.
The sooner you understand whether the tooth needs a filling, a crown, or more involved care, the easier the decision usually feels.