Sum of Returned Lookup Values in a Text Cell

I'm using the lookup formula below to search user comments in cell B1 to find individual words listed in column C, and return the adjacent number value found in column D.

=LOOKUP(9999,SEARCH($C$1:$C$837,B1),$D$1:$D$837)

The problem I'm running into is that excel only returns the number value for the first word that it finds, when I really want it to return the sum of the adjacent number values of all of the words it finds in the cell.

Example: the comment: "The stores should stock more makes and more current styles and colors", should give me a comment sum of 24 - 10 for "styles" and 14 for "colors", but excel is only returning a 10 for "styles".

Please help!
Thank you!!