Hi Jondel
Where is your Westie scratching.
Best that you do take her to see a Vet.
I have a Westie and she does not have that problem and has also been tested for it, but my last Westie was prone to a skin problem.
He was given an injection at first, then put on medication for it. He was actually prescribed Piriton, which is an Antihistamine, the same as humans can take. The Vet told me to buy it over the counter once he had been diagnosed with the problem as it would save me money in Vet fees.
Check her back to feel if there are any little lumps. If she does have that then it will be driving her crazy. Take her to be checked at the Vet anyway.