.htaccess - Change URL part to parameter and ignore the rest - wordpress

Question

I'm doing SEO optimization for a website and I need to transform a part of the url into a parameter. The URL format can still be changed if needed.
Basically I'm working with Wordpress and want to create a single page that would work for all products, but I need to get a specific product number from the URL.
The URL looks something like this:
www.example.com/product/[product-id]-brand-name-and-some-other-stuff
I want to transform the URL behind the scenes (meaning the URL won't change) to this:
www.example.com/product/?pid=[product-id]
I don't have much experience with htaccess and any help would be appreciated.
Here's the current htaccess file's content:
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /downloads/www.bqwatches.com/
RewriteRule ^watch/([^-]+)- watch/?bqn=$1 [L,QSA,NC]
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /downloads/www.bqwatches.com/index.php [L]
</IfModule>
# END WordPress

Answer 1

Try this rule just below RewriteBase line of your regular wordpress .htaccess:
RewriteRule ^watch/([^-]+)- watch/?pid=$1 [L,QSA,NC]

Answer 2

Update: Altered the solutions to account for the fact that a product id consists of two letters, then a number.
You do the following:
RewriteRule ^product/([a-zA-Z][a-zA-Z][0-9]+).* product/?pid=$1
To explain what's happening, it matches the part after the URL that begins with product/, followed by two letters and several numbers, and then any other characters. The letters-and-numbers get put into the pid parameter of the requested URL, and the rest is discarded.
If you pass it http://www.example.com/product/af1234-some-product, it converts behind-the-scenes to http://www.example.com/product/?pid=af1234.
You could also accept any two characters followed by a number, by doing the following:
RewriteRule ^product/(..[0-9]+).* product/?pid=$1
If the product id could be any character that isn't a -, then the following should achieve the same:
RewriteRule ^product/([^-]+).* product/?pid=$1