Struggling with teat size

Baby is 13 days old, last week we switched to size 1 teats as the size 0 she started to get nothing from them. She was drinking fine but in the past day and a half shes started leaking loads of milk from her mouth like the flow is suddenly too strong for her again. The health visitor came for the 1st time this morning and watched me feed her and said she was just a messy eater but im not so sure this is right.

Do i go back to size 0 again?

I feel awful, because of the heat she's been in nothing but a nappy, ive been wiping her down with damp cotton wool after every feed to clean up what she's spilling. As ive been writing this my husband discovered a bit of milk stuck in her armpit that ive missed and now she is sore 😭