naruto question. Did Orochimaru give himself a curse mark to boost his own strength?

I don't think so.  I'm almost certain that's never explicitly stated.  And if I'm right, the reason he wouldn't seems obvious.  The curse marks are rather a double-edged sword.  They incite rage and a lack of control in the subject AND they come from Jugo's enzyme and Orochimaru's chakra.  

No he didn't and can't.  The reason he developed them in the first place is because his own host bodies are too weak to withstand a true sage transformation.  So the Cursed Seals became an alternative way he could make use of sage chakra.  Empowering subordinates, crippling enemies in battle and acting as extensions of his own consciousness and life force. They weren't meant to empower himself physically.