As has been mentioned, it's almost impossible to come up with any useful notions without seeing you on the bike or even seeing the bike in its totality.

The shot of the bars, though the camera angle is wacky, gives me an idea though: your brake levers look like they're up quite high. What that means, possibly, is that depending on the angle at which your arms are approaching the bars, you may be bending back your wrists (i.e. flexion) to get onto the brakes, which in turn can mean not only nerve binding, but concentration of your weight over a smaller area of the palm.

My suggestion is to simply loosen the brake lever mounting clamp (maybe a 5mm allen) and rotate the lever towards the ground until something like a 7 o'clock position-- they look more like 8 o'clock now-- so that your wrist is in a more neutral position when covering the lever.

I'm guessing that because you're in Korea, you spend a fair amount of time in urban settings, and keep your hands on the brake levers often, but of course, there could be any other number of causes, but that's an easy, free adjustment to make before you start looking at some of the other possibilities, and making will result in more comfort and control whether it's the source of the problem or not.

I would advise you reposition your saddle to correct height before making this, or any other, adjustment. A low saddle can lead to its own problems when doing lots of mileage and putting out power.