White bubbly snot in baby

[Wineandchocolatebiscuits]

My baby has a cough for about a week and copious amount of snot which the last day or so has turned white and also weirdly has all these little tiny bubbles in it. Is this normal? She's been grumpy and a bit more sleepy today as well.

It looks like the top of a cappuccino! Very odd... not sure if we should be worried about her cough or not. She's developed a slight temperature this evening.