my mom overstayed her admission time by 10 days, but visa is still up-to-date. Can I come back to the USA? if so, is her visa still valid

If your mother overstayed her admission time by 10 days or by any days, her US visa is automatically canceled. She would have to obtain another visa from the American consulate or embassy to be able to legally return to the US Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.