Diaper sizes

Karina

So my 4 1/2 month old is in size 2 but I’m thinking it might be time to size up because she’s been getting these rashes on her inner thighs, anyone else have this problem or is it just the diaper? At her 4 month check she was only 13 pounds and she uses Kirkland and huggies little Snugglers and I’ve been having this problem with both diapers