You don't indicate what testing was done to provide the 90887. 90887 is a consultation to interpret and discuss "results" of psychiatric or other medical examinations and procedures." Your CPT 90834 is psychotherapy (face to face) and your 90887 is not face-to face. Medicare wouldn't pay the 90887, so most likely BCBS won't either.
Since they were both done same day but one has not much to do with the other, it's not likely to be paid with or without a modifier unless you have a specific E/M code to which would substantiate the 90887.
And to note.. don't let the insurance companies tell you how to bill.. they are not supposed to, they can make suggestions but the bottom line is you need to bill as per the documentation.