Updating products on backend doesn’t reflect on frontend

I have this magento store I just installed and configured according to guides Varnish cache.

Website now is blazing fast, but if I update a product (for example, add a description), even if I cache clean/flush, invalidate indexes and reindex, product page still shows stale data (ie none of the changes I just made).

How can I make sure that, anytime I update a product, I either invalidate/redo the cache for that product?