I need to inhibit myself from eating too many cookies.
"The changes in spending habits will probably inhibit the growth of new businesses."
Has and have are two forms of the infinitive to have Has is used for he, she and it, and generally speaking third person singular. (eg Richard has a lot of friends) Have is used for all other case...
Has is used in the present: Tom has a soccer tournament today. Had is for the past: Lauren had an ice cream cone three hours ago.