I've bought and installed Dawnguard but it wouln't show on the DLC list,
Is there a fix?

when you bought the DLC did you ensure the region code matches your disk's region code? (BLUS, BLES or BLAS code can be found on the box of the game)

hmmm no,where is it shown in the store?
and if i've mistaken,what do i do?

Baharu, it's only an issue if you've mixed regions, like an American disc and French DLC. But you sound like an American so it would be an unlikely scenario for one of us.

Actually I'm from Israel...
Means It's a problem?

when you go to the psn, and search up the dlc, in the description of it it will say the required region code for the dlc. if you accidentially bought the wrong region then... well then i dont honestly know what youd have to do, but id guess you can try emailing sony customer support to ask them if they'd be willing to give you a new one with correct region, or youll just have to buy it again, this time ensuring the region code matches