White blotches in paint??

Don't see the attached picture. But, could it be leftover wax that wasn't wiped off?

 

Looks like the clear coat is coming off.
If you have bird dropping problem where you parked, bird droppings are very acidic, it could be damaged from the bird dropping if you don't wash them off daily.

 

The fine cracks would indicate your clearcoat is damaged.

Do you park your car outside? Something had accelerated the aging of your paint. Your car isn't old enough for that to happen under normal conditions.

 

OP lives in the Phoenix, AZ area and parks outside during the day: 120 degrees F summer temps, black exterior color that absorbs all solar energy - not that surprising to see paint damage after 4 years.

The cost of the repair will depend upon the extent of the paint damage, might be necessary to repaint the hood and roof surfaces. In that case the price will probably approach $1K.

 

I had a brand new black Sentra that did that exact thing 2 years in the sun. That same strange white mottle. Its either bird or airplane
pollution.
Clay bar helped a little but black flat out sucks on a cheaper car. Mercedes and BMW's do ok with black as they have excellent paint.

I've only owned one black car in my life. Never again. The paint is such a pain.

 

So true. The tiniest imperfection becomes very obvious with a black finish.

Not to mention that the color is highly impractical if you live in a hot sunny climate - the car heats up much more when parked outside, the paint ages faster, etc.

However when the black finish is flawless, then the car looks very impressive. Too bad it takes so much energy and $s to maintain that appearance.

 

I think its bird crap that burns a pin hole in the clear coat and then further pollution creats that fungus looking thing below the clearcoat. I had that exact thing. At one point I took rubbing compound to it in exasperation and just ended up messing the paint up. Black is tricky.

One thing I have been doing for a long time and it really really helps is after I park it in the garage at night if I'm not to tired I'll get a
soft rag and wet it with water and wipe the hood off. Just the hood and mayeb the bumper.

But, no matter how much quality wax you put on our hoods in one days driving if you run your hand over the hood it has this weird tinny abrasive nothing there feeling. Like you never waxed it.
I guess its just a combo of thin aluminum, not very thick or quality paint, and a hood angle that gets wind beat and gets hit with everything.

But the wet rag rub down for bird crap really helps the hood.

Stone chips are another story.

Good Luck!