No, there is no restriction on travel during the H1B registration period. It will not impact your H1B lottery chances. But, if you plan to file H1B petition as Change of Status(COS), you should be back in US before your actual H1B petition is filed with USCIS. Your employer would include copy of I-94 along with your H1B petition to stay that you are inside US and in proper status. That way your COS would be approved.