Thanks for advice, comrade! I went ahead and did it myself after watching a few videos and reviewing your comments. You were right about the cause. The hood of the car was repainted, and it seem like they have done a pretty bad job on this. When I was sanding down the old paint, I discovered that they didn't even bother to sand the previous paint layers down. So I was literally sanding through layer of paint, primer, then another paint layer, and another primer layer until it was all evened out. The results are pretty good for DIY garage job, and I am pretty happy. Just need to polish it now.