How is my cat so dumb.

Hi, so I have two cats, both adults. One is five years old and the other is her mother. I took Mama Cat to the vet, who found that she had an ear infection and prescribed some ear drops. I just put them in for the first time at home without problem, but when Mama Cat approached Baby Cat, Baby started hissing and puffing up as if she didn't recognize her mother. I understand Mama Cat probably smells a little weird now, but is this a normal reaction?? I tried to encourage them near each other, but no progress. Mama Cat seems bewildered and sad. How is Baby Cat so dumb? So dumb, for real.