Hello dear.
I can be
ear ache,nappy rash,colic or as you said ear eruption.
Check her nappy area,is it sore?.if yes apply rash cream or can also use olive oil to soothe that pain.
If she is constantly pulling her ear or if there's any discharge or the area behind the ear is red,its
ear infection.Give her ofloxacin+
lidocaine drops(2 drops twice a day for 5 days).
If she is crying with her legs going upwards,moving around,could be colic.
Give her colic drops/execol drops and
massage the area.search for colic massage on youtube.You can give her green tea made up of ajwain seeds (a pinch) and few mint leaves in a cup of water and boil ot.Give her after straining this in sips.
It will soothe colic.
If its ear eruption,generally the child feels calm when you put a finger inher mouth.she will chew it for a moment.
Give her
teething drops or bonjela gel.
Hope it will help.
Wishing your child good health :-)