The design is the overall shape of the BLISTER PACK shown in the Drawings.Drawings of the design are included, in which:Figure 1 is a top plan view of the BLISTER PACK;Figure 2 is a right side elevational view of the BLISTER PACK;Figure 3 is a front side elevational view of the BLISTER PACK;Figure 4 is a left side elevational view of the BLISTER PACK;Figure 5 is a bottom plan view of the BLISTER PACK;Figure 6 is a back plan view of the BLISTER PACK;Figure 7 is a top plan view of a variant of the BLISTER PACK;Figure 8 is a right side elevational view of the BLISTER PACK of Figure 7;Figure 9 is a front side elevational view of the BLISTER PACK of Figure 7;Figure 10 is a left side elevational view of the BLISTER PACK of Figure 7;Figure 11 is a bottom plan view of the BLISTER PACK of Figure 7;Figure 12 is a back plan view of the BLISTER PACK of Figure 7;Figure 13 is a top plan view of a second variant of the BLISTER PACK;Figure 14 is a right side elevational view of the BLISTER PACK of Figure 13;Figure 15 is a front side elevational view of the BLISTER PACK of Figure 13;Figure 16 is a left side elevational view of the BLISTER PACK of Figure 13;Figure 17 is a bottom plan view of the BLISTER PACK of Figure 13;Figure 18 is a back plan view of the BLISTER PACK of Figure 13;Figure 19 is a top plan view of a third variant of the BLISTER PACK;Figure 20 is a right side elevational view of the BLISTER PACK of Figure 19;Figure 21 is a front side elevational view of the BLISTER PACK of Figure 19;Figure 22 is a left side elevational view of the BLISTER PACK of Figure 19;Figure 23 is a bottom plan view of the BLISTER PACK of Figure 19;Figure 24 is a back plan view of the BLISTER PACK of Figure 19;Figure 25 is a top plan view of a fourth variant of the BLISTER PACK;Figure 26 is a right side elevational view of the BLISTER PACK of Figure 25;Figure 27 is a front side elevational view of the BLISTER PACK of Figure 25;Figure 28 is a left side elevational view of the BLISTER PACK of Figure 25;Figure 29 is a bottom plan view of the BLISTER PACK of Figure 25;Figure 30 is a back plan view of the BLISTER PACK of Figure 25;Figure 31 is a top plan view of a fifth variant of the BLISTER PACK;Figure 32 is a right side elevational view of the BLISTER PACK of Figure 31;Figure 33 is a front side elevational view of the BLISTER PACK of Figure 31;Figure 34 is a left side elevational view of the BLISTER PACK of Figure 31;Figure 35 is a bottom plan view of the BLISTER PACK of Figure 31;Figure 36 is a back plan view of the BLISTER PACK of Figure 31;Figure 37 is a top plan view of a sixth variant of the BLISTER PACK;Figure 38 is a right side elevational view of the BLISTER PACK of Figure 37;Figure 39 is a front side elevational view of the BLISTER PACK of Figure 37;Figure 40 is a left side elevational view of the BLISTER PACK of Figure 37;Figure 41 is a bottom plan view of the BLISTER PACK of Figure 37;Figure 42 is a back plan view of the BLISTER PACK of Figure 37;Figure 43 is a top plan view of a seventh variant of the BLISTER PACK;Figure 44 is a right side elevational view of the BLISTER PACK of Figure 43;Figure 45 is a front side elevational view of the BLISTER PACK of Figure 43;Figure 46 is a left side elevational view of the BLISTER PACK of Figure 43;Figure 47 is a bottom plan view of the BLISTER PACK of Figure 43; andFigure 48 is a back plan view of the BLISTER PACK of Figure 43.