My connection to a Mysql DB has been blocked after spamming queries, for how long?
SUGGESTION
If you have the RELOAD privilege, you can run this
mysql&gt; FLUSH HOSTS;

According to MySQL Documentation on running FLUSH HOSTS:

Empties the host cache. You should flush the host cache if some of your hosts change IP address or if the error message Host 'host_name' is blocked occurs. (See Section B.5.2.6, “Host 'host_name' is blocked”.) When more than max_connect_errors errors occur successively for a given host while connecting to the MySQL server, MySQL assumes that something is wrong and blocks the host from further connection requests. Flushing the host cache enables further connection attempts from the host. The default value of max_connect_errors is 10. To avoid this error message, start the server with max_connect_errors set to a large value.

You should run this command
SELECT host,Reload_priv FROM mysql.user
WHERE user = 'mysqluser';

If nothing appears, then you do not have the RELOAD privilege. Consequently, you have no choice but to contact the system administrators to run FLUSH HOSTS; for you.
ALTERNATIVE SUGGESTION
Ask the system administrators to configure max_connect_errors in my.cnf
[mysqld]
max_connect_errors = 18446744073709551615;

To avoid restarting mysql, ask the system administrators to run this
mysql&gt; set global max_connect_errors = 18446744073709551615;

Give it a Try !!!