Making Outline thicker—Clipping Mask

[Davis5F93]

Hello,

Is there a way I can make my clipping mask outline thicker? 

 Every time I try to make the outline of the 24 thicker, the outline of the flowers increases as well. 

 

Here is a photo of my layers 

[Monika Gause]

Select only the mask path with the direct selection tool. Then try again to adjust the line weight.