arcano: this word occurs in 162. ab here suggests strongly that it is a personal name. It seems likely that we have the right-hand edge of the leaf with an the start of a word which continued in the next line.
The first trace does not look like s; perhaps we have a word ending in -s followed by et.
libros: before the first letter there is the descender from r in the previous line. Given the knowledge of Virgil, and perhaps of Catullus, attested at Vindolanda (118, 119), there is no reason to doubt the availability of books.
exse-: this suggests part of the verb exsequor, continuing in the next line (see line 1 note).