2 Weeks is nothing depending on the size, weight it can last a few weeks to a few months.
The first thing to do is to re-assess your husbandry sometimes things work for a while and then they don't so making so changes may help if this behavior persist.
You also have to remember that 800/1000 grams is when they hit the wall which is common for BP, considering the size at less than a year I am not surprised to see some refusal, you might want to feed a little less and skip a meal every now and then.
As for a vet I don't see why a vet would be involved with an animal weighing at 800 grams at a year.