Adiyen has some physical ailments that my mensurating period stretches between four to thirty days: should I refrain for four days or the entire period of mensuration for routine work? Can I enter the kitchen after five days? Can I clean the vessels used for Perumal after five days?

As per the tradition, one needs to stay away for three nights and after taking bath on the fourth day, we come for routine work. But the fourth day is also considered impure. Though there may be physical discomfort after the fourth day, one need not remain separate.
There is no need to stay separate until the fifteenth day while days sixteen and seventeen are equivalent to the fourth day of impurity. If the discomfort prolongs after seventeen days, then one must stay separate.
While scriptures do not object one from lighting lamps or cleaning thiruvaradhana vessels and it is not wrong if one feels uncomfortable in doing this work, they can refrain from them, again it depends on one’s mindset.