It could be milk rashes. Typically, milk rashes are an allergic reaction to milk formulas or a hormonal reaction to your breast milk. At other times, these rashes can also appear if milk had dried up on your baby’s face and wasn’t wiped clean. These rashes may also appear if your child’s skin is always wet with saliva or comes in contact with harsh fabrics or chemicals like perfumes or colognes. You can use clean cloth and wet with cool-boiled water to clean baby's mouth after each milk feed. The link here has other suggestion like use jasmine flower and Wondercreams to get rid the milk rashes. http://sg.theasianparent.com/milk-rash-remedies/
Not too sure which type of rash are you referring to. Here is a link with skin conditions (with photos and not limited to rashes found at mouth area) common in children: http://www.babycentre.co.uk/l1038755/childhood-rashes-skin-conditions-and-infections-photos And here's another link stating the different types of rashes and suggestions on how to treat them: http://www.parents.com/baby/health/rashes/rashes/ In general, rashes can be treated locally with antiseptic or antibacterial treatment. Contact your doctor if the rash is accompanied with fever, headache or sore throat.
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