There is no specific medical treatment for HFMD. You can take steps to relieve symptoms and prevent dehydration while you or your child are sick. Take over-the-counter medications to relieve fever and pain caused by mouth sores. These medications can include acetaminophen or ibuprofen.
Wash the skin with lukewarm soap and water, and pat dry. If a blister pops, dab on a bit of antibiotic ointment to help prevent infection and cover it with a small bandage. Make sure your child drinks plenty of fluids to stay hydrated.

I would give panadol or nurofen

check at the chemist to see if they have anything to recommend

how did it turn out?

What did you end up using?

We have pain stop and its very good and helps them sleeps as well

Phenerghan and Cammonile lotion worked for me

You can try pain stop.

See a naturopath for a natural sleep remedy.

sadly all you can really do is try and keep their fluids up and try and make them comfortable

Wanted to know aswell, thanks for posting.

Pine tar baths and plenty of pain relief. It is horrible!

And/or panadol or neurofen for the pain

Talk with the chemist as they may have something you could buy over the counter and use.

dermaveen oatmeal wash to help with the pain. it helps soothe the skin