A couple of things...
1) Without a script, macros don't have a way to change a character sheet or token. You'll have to manually track the loss of HP.
2) You can't reuse rolls like this: [[$[[0]]]]. You can reuse the roll by invoking the roll marker ($[[0]]), just not in another roll. Typically if you want to reuse a roll in another roll, you structure as much of the roll as nested, first, because if it happens at once the roll will be interpreted. That way you can pull out the bits you want, later. This one doesn't make a whole lot of sense (for reasons I'll say in a minute), so let's say that what you really wanted was to take roll $[[0]] and add 2 to it. You might be tempted to right it: [[ $[[0]] + 2]] ... but that wouldn't work. Instead, take advantage of the fact that text you put between the double braces of a roll template won't show up:
@{Camilla|wtype}&{template:atkdmg} this text won't show up. put anything here{{mod=+1}} this is also hidden {{rname=Hidden Stuff}}
Stuff the roll into one of those gaps and stack all of it up the first time it shows up. Your roll $0 is the first roll in your macro, which I'll use, below:
[[ [[@{Camilla|d20}cs>20 + @{strength_mod}[STR] + @{pb}[PROF]]] + 2]]
Provided this is the first roll in your macro, your Roll $0 is still the same roll. But now your Roll $1 is the value of Roll $0 + 2. So you can use these things in your template between the double braces:
@{Camilla|wtype}&{template:atkdmg}[[ [[@{Camilla|d20}cs>20 + @{strength_mod}[STR] + @{pb}[PROF]]] + 2]]{{mod=+1}}{{r1=$[[0]]}}.....{{somewhere else=$[[1]]}}...
3) As for why that doesn't make sense, it looks like you're trying to implement a particular Blood Radiance ability on the sheet (maybe identified by the number on the back end of the name)... but that number will never be rendered to the template. Even when you enclose it in more double brackets of another inline roll, all you're doing is changing the roll marker that gets left in the line. Nothing in a standard macro/ability can extract the value of an inline roll. Scripts can do that... my ZeroFrame script lets you append .value to any inline roll to extract the value in situ, after inline rolls are parsed but before the line is given to the chat output. Short of something like that -- or me better understanding what you're trying to do there, I'm not sure what to do with this part
4) You don't have the leading double brackets for the bit of text after that r1 part. R1 looks closed:
{{r1=[[@{Camilla|d20}cs>20 + @{strength_mod}[STR] + @{pb}[PROF]]]}}
...but then the next bit looks like the same roll, but without being in a template part (no opening double braces) and without being in an inline roll (no double brackets):
@{Camilla|rtype}cs>20 + @{strength_mod}[STR] + @{pb}[PROF]]]}}
5) Finally, after all of that, I'm not terribly familiar with that sheet, so while I can help spot syntax errors, reaching into the sheet to know whether it will take a completely new ability is above my pay grade.