After doing spell getting mojo bag, I plan on dressing it every week. Is that the norm?
Yes, sressing it weekly is the norm.
Can you add things to the mojo after finished, and if so how do you do it?
If you made the mojo yourself, you will understand that adding things (except to a Nation Sack, which is a particular type of mojo) will require you ti untie it, pray over what is added, re-dedicate the bag, re-smoke or warm or breathe into it, re-tire it, and re-pray over it. Most people don't ddo that, but you have the option, if you wish to do so.
Can you dress it with oil and sachet?
Mojo hands are only fed with liquids, not with powders. Some folks include powders inside them, however. The powders will sift out through the cloth fibers and may perfume the wearer's bosom.
Can you dress your self by annointing your forehead and or adding sachet on a regular basis till you start getting results?
Better than re-opening the mojo to add powders would be to dress your own hands or forehead with the oil and to dust yourself with the powder, or blow the powder very lightly over th area where you will be working.
Good luck!