#!/usr/bin/perl
my $line;
while (my $line = <DATA>){
if($line =~ m/<span><p>(.*)/){
$line= $1;
$line =~ s/</<\/p><p>/g;
print $line;
}
}

__DATA__
<span><p>This affected me deeply because < I was being treated for depression then. < felt she was replacing me as mother and grandmother.

##</code><code>##

This affected me deeply because </p><p> I was being treated for depression then. </p><p> felt she was replacing me as mother and grandmother.

##</code><code>##

<span><p>This affected me deeply because </p><p> I was being treated for depression then. </p><p> felt she was replacing me as mother and grandmother.