I second the bike fit suggestion. Wider tires are also a good idea. On top of that, you might want to try double wrapping your bars with bar tape. I usually run a cork tape underneath the Lizard Skins tape. I like the feel of the Lizard Skins tape and it’s on all of my road and cross bikes now (4 total). It does get a little pricey as far as tape goes, especially since you have to spend money on two sets of bar tape for one bike. But that’s why I usually just use a cheap cork tape on the bottom. It makes the handlebars a little thicker, which opens up your hands and increases blood flow. Also try relaxing your grip as much as you can. I remember in one of the first crits I ever competed in my hands repeatedly went numb because I had a death grip on the handlebars.