In case the inner scope isn't just a plain block, but a subroutine, you can use PadWalker to get at the outer scope(s):

use PadWalker qw(peek_my);

my $a=10;
sub {
    my $a=11;
    my $my = peek_my(1);    # one level up

    print ${$my->{'$a'}};   # 10
    print $a;               # 11
}->();
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This isn't meant for everyday consumption, though... — better use unambiguous variable names.