Red Line Across Nipple, Soreness, No Discharge, Swelling, Skin Problem, Scratch With Fingernails
There are 2 possibilities here.
Either this could be a skin related problem or it could be a simple scratch that your daughter may have made with her finger nails.
Often kids,may scratch themsleves without realising it.So the important thing to do is differentiate between these possibilities.If it is a skin related lesion it could be allergic reaction,and she would possibly have symptoms like itching,pain etc.The other possibility is that a simple scratch has become infected.If this has happened before then its possible that its a simple scratch.
You can apply an antiseptic cream or neosporin powder for a couple of days.
Keep the area clean and dry.
Make sure your daughter doesnt scratch there(which is possible if itching is present).
If the soreness doesnt reduce in a couple of days,then a dermatologist advice might needed.
Any clarifications are welcome.
Regards,