I assume you are working with Photoshop? You could approach your problem by clicking the outmost right button on the top when using the text tool (called "Toggle Character Settings" or something). There you can adjust the tracking, scale, leading etc of your font, perhaps that helps. Changing the anti-aliasing mode from the usually predefined "strong" to something else might also be a solution.

If none of the above make sense or work out, just upload a picture of your problem. We'll find a way then