If the respondent does not request a hearing within the time prescribed by §3.504 of this subpart and the matter is not settled pursuant to §3.416 of this subpart, the Secretary may impose the proposed penalty or any lesser penalty permitted by sections 921 through 926 of the Public Health Service Act, 42 U.S.C. 299b-21 through 299b-26. The Secretary will notify the respondent by certified mail, return receipt requested, of any penalty that has been imposed and of the means by which the respondent may satisfy the penalty, and the penalty is final on receipt of the notice. The respondent has no right to appeal a penalty under §3.548 of this subpart with respect to which the respondent has not timely requested a hearing.