Please tell me this is 'just wind', as my mother says (o, she of the school of old wives' tales! I can never get any sense out of her, and she's not even 50 yet!)!

DD2 has this funny purple-blue colour around her mouth, mainly below her bottom lip. Yes, she is a very gassy little thing, always burping and fluffing, so I'm hoping my mum is right and that she's just got wind... I'm worried that it might be something more serious though, maybe a problem with her circulation? The rest of her body (hands, feet, torso etc) is beautiful pink, warm, and healthy-looking... it's just the area around her lips that have me concerned. She's not unsettled or seeming to be in any pain (DD1 had a bit of constipation at a few weeks of age and I *knew* she had a pain in the gut, she carried on like a pork chop until we got some Coloxyl into her), but her feeding has gone from being exceptional (ie, CONSTANT) to pretty sporadic (I'm having to wake her for feeds every few hours, she will sleep all day if I let her)...

I just don't know what I'm looking at, and whether it needs the attention of a doctor or a trip to the ER (ie, more urgent than a visit to the GP tomorrow while DD1 is at daycare). Can anybody help me out?