^depending on what kind of octopus she's supposed to be modelled on those are either papillae (meaning tentacle-like projections from the skin in the case of octopi, primarily used in camouflage) as eg. the wunderpus and its close relative mimic octopus have above their eyes, or fins as in the suborder Cirrina (used for swimming) - probably the latter and likely based on the kewt umbrella octopus Ophistoteuthis californiana aka "flapjack octopus". The uguu kawaiiis stronk in that one so predictably the fins appear a lot on cephalopod-themed monstergirls who're intended to be cutesy an' stuff.
^errrrr... you do know her hair's quite long, right? Even with much of the length tied up in those elaborate faux-nekomimi twintails it comes down to like her buttocks.