Samson should fall into the category of the Nazarite, even if his circumstances (given over to this vow from birth for a lifetime of service, according to the Word of the Lord) were rather extraordinary, and not voluntary and occasional/temporary according tp the law's express stipulations, Num.6.
Samson's violations of the vow under which he lay should be viewed as failures (sins) of the flesh--failures that every man must commit, because none of us is able to keep the Law perfectly. A temporary Nazarite was expected to "repent" of any failure in his vow-keeping, and to start over literally from the beginning of his vow. A "permanent" Nazarite should be expected to "repent" as well, despite the fact that genuine perfection would no longer be possible. "Renewal" is perhaps the better term.
And in Samson's case, I think there is clear evidence of both repentance from sin, and renewal. In losing his hair, Samson grieved away the Spirit (who was his real Source of strength). And, indeed this was only the last breakage of his link to his Nazarite vow, which had seen many violations of its stipulations, not to mention flagrant violations of the moral law. [The Nazarite vow was supposed to be "going above and beyond" the normal commitment of an Israelite in devotion to God.]
But God's acceptance of Samson's repentance and faith is shown in the event of his sacrificial death, in which he (by the power of the Spirit once again) gave his own life to destroy the destroyers of God's people.
