In my state, which is not yours, the Child Support Enforcement Agency would be one of the lien holder claimants, except they probably have a higher priority than most other lien holder claimants, such as medical providers.
I don't know what your WC claim is worth. You will have to discuss that with your attorney. However, I would expect the child support enforcement agency to get the entire 19k. Your atttorney fee may or may not come out of the remainding funds. This one definitely varies by state. Ask your atttorney about that one as well. You also should ask your attorney about any medical lien holders. If there are medical lienholders they will be paid from whatever is left over.
While you may not be able to reduce the lien of the Child Support Enforcement agency, there may be some room for negotiation with the medical lien holders, if any.
As a practical matter, however, the value of your claim in the WC system cannot be increased solely because of the CS lien.
Finally, if this offer is the initial offer, there may still be room for further negotiation about the final amount of that lump sum and whether that does or does not include future medical expenses. If you don't have an attorney for your WC claim, now would be the time to get one.