Flat Tire

[BsixSfour]

Ok so here's what happened,

I parked wherever I went, and when I got out, I heard some hissing. Thought about it, was like naa, then thought about it again.. and I was like wait.. then I get near my front right tire and air is coming out of the side of the valve (I think) - pretty quickly - I do have a cap on it.
I move it around till it stops, it helps while the car's not moving.

The tires are new with ~1k miles on them. BF Goodrich, don't know anything else (will check on them tomorrow if more info is needed).

The I drove home because I didn't have the spare with me, and went pretty slow to not go over any bumps and bend the rim.
Obviously when I got home it was flat.

Questions:
- Should I slap the spare on as a permanent solution? (The spare has Pirelli tire, and I don't know if having 3 of one tread, and then 1 of another tread is bad/fine.)
- Or should I slap it on and take it to the dealership and have em get me another BF Goodrich tread/rim, or fix the valve. (I do have warranty)


Thanks in advance.

PS: stock rims
PSS: it was dark and it still is so I can't tell if there are any cuts on the rubber part of the valve, but I will check tomorrow.

[MOFSTEEL]

You just have a faulty valve stem.
Throw the spare on if you need to and have the dealer put in a new stem.
Not a big deal.

[BsixSfour]

Thanks!