11 month old with a bad latch

So Dd is 11 months and she only just cut her 1st tooth a couple of days ago. For the last couple of weeks since she started teething her latch has deteriorated to the point I am starting to wonder if she is forgetting how to do it. She doesn't open her mouth properly, even if I can make her do it she doesn't take it in her mouth properly and sucks funny. It's not overly painful ( tender but not toe curling pain) but it is incredibly ineffective. She's taking 5-6 minutes to get a let down each time and even after let down gets angry at the breast pretty quickly. I don't know what to do to improve it. I realise her gums are sore but because she is teething so late, it looks like she'll be getting a number of other teeth very soon so I don't see this ending soon. Any ideas in how to fix a big babies latch especially seeing as its obviously hurting her.

Anyone????

Probably won't be too much help, but have you tried teething pain relief a little while before each feed? Or use something like brauers? An amber necklace all the time? Cold flannel to chew on before feeding?
We had some minor attachment issues through teething and I used to say "open wide" and really concentrate on correct attachment (she was at the age where she could understand and would open her mouth wide). Worked for us but as I said our issues were minor.
Hope this helps.