the simple and easier one
My daughter does the same thing she is almost 5 monthsI asked the doctor about it and she said babys will do itShe isn't teething or anythingJust in that phase where they are learning new things We give her a new blanket everydayIf spits up on one we give her a new oneWe still wrap her up at night and she gets herself unwrapped and sticks the blanket in her mouth.
I think all babies do this, my son is 4 months and he loves to bury his face in a blanketI have this cute little blanket that has a stuffed bear's head in the middle that he can chew on and when he naps he will use the blanket to cover his eyes.
It's probably just a habit that makes her happyMy oldest had a blanket he slept with as a baby and he used to shove the corner so far into his face it would go up his nose a littleIt was gross but it made him happyJust keep an eye on her and wash the blankets a lot.
my daughter done the same thingi dont know if she liked the feeling of the blanket on her face or what it was but really loved to do itshe is now 8 months old and still does itif u are worried take the blanket away at nightshe may be teething or just like the way the blanket feelsgood luck.