Unfortunately, yes.

It actually did take a small chunk out of your newly increased HP.

You decide you should check your new stats.

Dark Mage

Lv 3-4 (Equipment)(Boss)(Total)
HP 30-40 (0)(15-20)(45-60)
MP 45-60 (20)(23-30)(88-110)
Atk 2-3 (0)(1-2)(3-5)
Def 1-2 (0)(1)(2-3)
Mat 7-10 (2)(4-5)(13-17)
Mdf 5-7 (1)(3-4)(9-12)
Agi 4-6 (0)(2-3)(6-9)

Casting Speed 100% (10%)(50%)(160%)

Skills:

LEVEL UP!
Illusion LV 2: 20 MP Temporarily conceals the user from enemies. Lasts for 6 seconds for every point of the user's Mat minus 1 second for every point of the enemy's Mdf.

Soul crush: 10 MP Temporarily lowers the opponents Mat and Mdf by 50% lasts for the duration of combat.

Dark orb: 5 MP launches a dark orb of power towards the target, dealing twice the damage of a basic attack while taking twice as long to cast.

Aura:

Soul Drain: Drains 1 MP/s from all enemies. Once all MP is drained, compatible skills are made available for the user's use.

Well, no new skills, but illusion leveled up. 17 * 6 is 102. That's almost two minutes of invisibility before subtracting the Mdf.

You decide to open up your stat menu now to see how much health you have left.

Dark Mage

Lv 4
HP 50/60
MP 110/110
Atk 5
Def 3
Mat 17
Mdf 12
Agi 9

Casting Speed 160%

Skills:

Illusion LV 2: 20 MP Temporarily conceals the user from enemies. Lasts for 6 seconds for every point of the user's Mat minus 1 second for every point of the enemy's Mdf.

Soul crush: 10 MP Temporarily lowers the opponents Mat and Mdf by 50% lasts for the duration of combat.

Dark orb: 5 MP launches a dark orb of power towards the target, dealing twice the damage of a basic attack while taking twice as long to cast.

Aura:

Soul Drain: Drains 1 MP/s from all enemies. Once all MP is drained, compatible skills are made available for the user's use.

So it took out 10 HP. As you have no way to heal, and all the creeps between the entrance and you are dead, you're just left a sitting duck in your room.