[Freedom.]

Nope.

Code:

PlayerTextDrawColor(playerid, txtpDmg[playerid], ADD_COLOR_CODE_HERE);
PlayerTextDrawColor(playerid, txtpDmg[playerid], COLOR_RED);

You can use this.
https://sampwiki.blast.hk/wiki/TextDraw_Text_Codes

Code:

format(strJoin, sizeof(strJoin), "~r~%d", 10+amount*-1);
PlayerTextDrawSetString(playerid, txtpDmg[playerid], strJoin);