Furthermore, you add a 1/4 of your dex modifier to your AC
I don't see the point...

corrosive blood dealing d6 acid damage per 3 HD you have against those that injure you with melee weapons
Natural or non-reach melee weapons.

Corrosive blood improves to affect any creature who hit you within reach.
Is that meant to be hit all within reach, when you are hit?

2nd - You gain +1 Hp/level.

4th - You gain +1 hp/2 levels you have.
Are those suppose to be the other way around, or perhaps the second should be +2/level?