score:4
As someone that had first-hand experience of this (ie, I did exactly the same thing!) I can tell you that it's fairly simple.
Once your temporary license expired you are "unlicensed" - you will have been in the state long enough that technically your home-country license is no longer valid in California, and your California license is expired.
Thankfully there's a simple solution - just go into the DMV, let them know what happened, and they will give you a new temporary license for another 60 days. No further written test required.
I'm sure if you do this too many times they will eventually take issue with it, but I had no problems doing it once.
When you come to do the driving test you'll likely find it very easy. They seem to go easy on people who have had their license in a foreign country - I didn't even have to do a reverse park as a part of mine despite that being a mandatory part.
Upvote:2
If you're visiting or a resident, it'll differ.
From the DMV page, if you're a visitor:
If you are a visitor in California over 18 and have a valid driver license from your home state or country, you may drive in this state without getting a California driver license as long as your home state license remains valid.
If you're becoming a resident, however:
If you become a California resident, you must get a California driver license within 10 days.
If you have a license from another country, you will be required to take a driving test, for which you have three chances to pass. If you fail three times, you do not meet their criteria to receive a drivers' license 'transfer' from another country, and as such will not be issued a license.
At this point, you'll have to speak to the DMV about what happens next. Likely it'll consist of getting some driving lessons and reapplying, but you may find you're not allowed to legally drive until you've completed these steps.