Blood Sacrafice

After the activation of the spell you need to roll self damage. A weapon get an extra 1d4+CON damage on it's next attack. You can stack this effect multiple times. The damage you take will depend on how many time you roll.

1st roll 1d4 Self damage,

2nd roll 1d6 Self damage,

3rd roll 1d8 Self damage,

4th roll 1d10 Self damage + Exhaustion

5th roll 1d12 Self damage + Exhaustion 

After reaching Character level 15

you can use it up to 10 times but each roll after the 5th will inflict 

roll 1d20 Self damage + Exhaustion

Exhaustion: In you next turn you lose one action and you can't add you'r HIT/DC to you'r next attack.