I am looking for Permethrin 5% cream to deal with some mites before I scratch my skin off. I've been to 5 pharmacies on Koh Samui and no one seems to carry anything stronger than topical antihistamines.  HELP!! 

Try going to a hospital or a clinic. They may have it or can get it. 

They might not know what you are looking for................Hecin is the name of one although it is Permethrin 1% ww which should be enough.

The usual medication used here is Scabicide Emulsion, white fluid in a biottle. Does not contain permethrin but rather benzyl benzoate, which works just as well  https://www.ncbi.nlm.nih.gov/pubmed/2472724

 

Ask for "Scabicide" and if necessary show this picture:

 

 

For what it's worth, Permethrin 5% cream is readily available at many pharmacies in Thailand now.

Are you sure its mites and not ringworm ?