Your blood turns acidic and you learn how to spray it around you in a radius as a reaction to taking damage.You may inflict that damage to your self but it takes an action to do so
The spell becomes stronger the more missing hit points you have and you are unable to use it if you have full hit-points. Everyone caught in the radius must make a dex saving throw taking half damage if they succeed.
Missing 1/4 hit-points or less: 2d6 20ft radius
Missing 2/4 hit-points 3d6 30ft radius
Missing 3/4 hit-points 4d6 40 ft radius
Withing 5 hit-points from death 6d6 60ft radius
At higher levels: Add 1d6 to the damage roll for every level higher than 2nd. If you cast it at 5th level or higher any creature that fails the throw is also blinded unless their eyes are covered.
You grow acidic glands out of a part of your body and you can spray a 60ft long and 5ft wide line of acid. Each creature in that line must make a dex saving throw, taking (2d6+2) acid damage on a failed save or half as much on a successful one.
At higher levels: When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot level above 1