You can try applying a cool compress to the pimples on your thighs and even putting some moisturizer on the pimples.
Another option is to apply some Apple Cider Vinegar to the pimples on your thighs 2 to 3 times per day using a cotton ball and then leave the Apple Cider Vinegar on the pimples until it dries.
It may take a week for the pimples on your thighs to fully go away with the Apple Cider Vinegar but it should work as I've used Apple Cider Vinegar to get rid of Pimples on my face before.