The recommended therapeutic dose of Lexapro for the
treatment of anxiety is 20 mg. The fact that you report that the
Lexapro was effective for you is a good thing, and the next logical step is to try a dosage increase.
Now, the thing is, you have to give the new dose some time, just like you did initially when starting Lexapro. Ideally, you should start seeing improvements after a few weeks, but it's not unheard of to need 4-6 weeks to be able to see the effects.