It doesn't say forever or that forever lasts during a finite period.
In Rev 10:6, the NASB translates it correctly...
and swore by Him who lives forever and ever, WHO CREATED HEAVEN AND THE THINGS IN IT, AND THE EARTH AND THE THINGS IN IT, AND THE SEA AND THE THINGS IN IT, that there will be delay no longer, (Rev 10:6)
G5550
χρόνος
chrónos; gen. chrónou, masc. noun. Time. This word perceives time quantitatively as a period measured by the succession of objects and events and denotes the passing of moments. Another word, kairós (G2540), season, the time of accomplishment, considers time qualitatively as a period characterized by the influence or prevalence of something. Chrónos is a period of measured time, not a period of accomplishment as kairós. Chrónos embraces all possible kairoí (pl.), and is often used as the larger and more inclusive term, but not the converse.