The map lite has only a single ethernet port, you shouldn’t (until you have become more expert with RouterOS) change its IP address (192.168.88.1), you can add a second address to that same port.
The device should then be remain accessible through the default IP.
In any case you could (should) use Winbox for configuration of a Mikrotik device, and Winbox has two ways to access a Mikrotik device, the “normal” one though its IP but also one through its MAC, so you normally can access it even if no IP is configured for the connected port (but not in all cases).
This said, only changing the IP address shouldn’t by itself prevent connection, it is possible that there is some firewall rule or some other setting in your current configuration that is “tied” to the default 192.168.88.1 address and does not allow a different IP connection
It is possible that you have something that classifies your ethernet port as WAN when you modify it, and WAN is not allowed by default on Mikrotik to access the router/AP, see also this:
http://forum.mikrotik.com/t/just-configure-map-lite-as-an-ap/152670/1
You should post your configuration, according to this post:
http://forum.mikrotik.com/t/forum-rules/173010/1
so that it is possible to point you to the culprit configuration line, cannot say the map lite, but most Mikrotik have:
/ip firewall filter
add action=drop chain=input comment="defconf: drop all not coming from LAN" \
in-interface-list=!LAN
/tool mac-server
set allowed-interface-list=LAN
/tool mac-server mac-winbox
set allowed-interface-list=LAN
but there could be many other possible reasons.