Dealing with reflux?

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Is anybody dealing with reflux in their baby? My daughter is 12 weeks old and in the last couple of weeks developed reflux that doesn't seem to be going away any time soon. She doesn't vomit luckily, but she does spit up a little bit after most feeds and often gets a sour look on her face like she's tasted something gross before grizzling. I believe it's started giving her grief at night aswell because she's been waking a lot more. I've elevated her mattress, but it doesn't seem to be helping. Any other tricks you can recommend? Is there some kind of medicine I can give her? I use Infants Friend to help her pass wind after her feeds, so thought there might be something similar for reflux..?