| No it is not generally permissible to include a prior years expense or income items into a subsequent tax years tax return. The IRS does not allow for this provision! I would recommend that you amend your 2007 year tax return to include omitted items of expenses.
Also, I do agree that you made a mistake but it is easy to rectify by filing an amended tax return, and I would not ignore these items of expenses as they will provide you with some type of tax benefits.
There is no worst case scenario other than not amending will cost you in terms of having a reduced tax benefit in 2007 and that you have not correctly reported your business income or losses for 2007. | 
