Madam says life is a sonnet and we are doomed within its strict structure. But we have the freedom to say whatever we can within its stifling form. So please keep your Iambs ready, neatly cut and if the syllables spill use an inverted coma. But fit the syllables within the allotted emphasis.
Remember you have just fourteen lines. Not all of them are of uniform size because some syllables are more equal than others. Cut out your love for uniform size. Let them spill if that cannot be helped and use your punctuation with a little license.
You do not have much to say by the twelfth line and you are already in the epigrammatic mode? Well yes that is how it happens in life as in sonnet. If nothing else you use the epigram for the headstone.