I just realized that I canned some potatoes for 25 minutes instead of the recommended time of 35 minutes last night. The jars all sealed. My question is, do i throw those out or do i just have to use them quickly? Thank you in advance, I'm new to canning potatoes.
Joe's comment is correct.
If you haven't canned them as long as the recommendation then you can't have confidence that they will be safe for a long period at room temperature.
Your options are to try again or treat them as not shelf stable.
The downside with trying to can them again is that the food is likely to be hopelessly overcooked. For something like potatoes, I don't know how much of a difference that will make as they will be thoroughly cooked anyway from the first time. If the potatoes have broken down into a mush, I would not recommend this strategy. The canning recipes are tested against food in a particular state. Potato chunks in liquid would conduct heat differently than mashed potatoes.
There is also the downside that you will have to use new lids which is an added expense, albeit small.
If you treat them as not shelf stable- simply put the jars in the fridge and use them soon as you would any leftover, cooked, potatoes. Realistically speaking, I believe you will find that they will last a long time in the fridge as they would have been sterilized- just not to a high enough confidence level.