Front end corrosion

I honestly don't think there is an easy answer here. Unless you are skilled in paint and body work yourself.
It's a 2004, so I'd imagine the rest of the vehicle is not pristine?
Refinishing and repainting the hood would obviously fix the problem, but then I think the hood would look incongruent to the rest of the vehicle.
If I'm underestimating how good the rest of the vehicle looks? Sorry.

 

Same problem in the same general area of my car's front hood. Mine is 2009 so it is not very old. The unusual thing is that it is rusting from inside the paint. No damage to paint surface itself, just a bubble similar to one shown.

Any one else seeing bubbles in front hood on undamaged paint?

 

i've seen ed china from wheeler dealers sand it down and apply a special rust stopping compound before repainting. all the best!

 

Pretty straight forward. If you want to do it your self pop the emblem off and open the hood. Protect the fenders and block sand down the hood with 220. Sand out all the rust area's to the metal but don't sand to deep as that may require some surface bondo. The whole hood doesn't have to go to the metal just the rusted area's.

Don't let the hood sit with bare metal.
Then buy a can of professional spray primer for aluminum and spray can of fish eye killer or degreaser body prep. Mask the car off. Wipe off hood with degreaser. Prime the hood with one thin coat and let dry. Prime again one thin coat. Block sand the hood again with 400. Wash off with soap and water. Prime again 2 thin coats.
Everytime you paint degrease first.
Wet Block again with 600 real light. Wash off and look for any uneven area's or scratch marks. They may need to filled with putty. Final prime coat.
Your in at abut $35 so far.

Go to the Toyota car dealer and nose around and find the car detail guy that touches up dents in the lot.
He's usually a sub contractor. One at every dealer.
He can come to your house for cash and paint the hood in your driveway and if he's good do a pretty good job at a fraction of the cost of a bodyshop. He will charge $150 and that should include the paint. Toyota paint is called Wanda.
Its all abut the prep job. It's easy. I use one guy for a while now. Does a good job.

Or a bodyshop will charge you $600.