I have ra and i got small hand deformity am taking methotrexate every saturday and folic acid every sunday.can that help stop the development?

Maybe: The evidence that Methotrexate alone can prevent damage is not that impressive. In patients with early damage i personally prescribe combination therapy with a tnf agent and methotrexate.

Yes, sometimes: Methotrexate is a first line therapy for RA in the us and most other therapies are combined with Methotrexate unless it cannot be used. If inflammation is continuing the addition of a biologic agent (humira, enbrel, (etanercept) simponi) may help prevent longterm damage. They have been shown to provide added benefit.